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How is the `rm` used? | rm [OPTION]... [FILE]... |
What is the detailed desciption of the `rm`? | This manual page documents the GNU version of rm. rm removes each specified file. By default, it does not re‐
move directories.
If the -I or --interactive=once option is given, and there are more than three files or the -r, -R, or --recur‐
sive are given, then rm prompts the user for whether to proceed with the entire operation. If the response is
not affirmative, the entire command is aborted.
Otherwise, if a file is unwritable, standard input is a terminal, and the -f or --force option is not given, or
the -i or --interactive=always option is given, rm prompts the user for whether to remove the file. If the re‐
sponse is not affirmative, the file is skipped. |
What does the command `base64` do? | base64 - base64 encode/decode data and print to standard output |
How is the `base64` used? | base64 [OPTION]... [FILE] |
What is the detailed desciption of the `base64`? | Base64 encode or decode FILE, or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --decode
decode data
-i, --ignore-garbage
when decoding, ignore non-alphabet characters
-w, --wrap=COLS
wrap encoded lines after COLS character (default 76). Use 0 to disable line wrapping
--help display this help and exit
--version
output version information and exit
The data are encoded as described for the base64 alphabet in RFC 4648. When decoding, the input may contain
newlines in addition to the bytes of the formal base64 alphabet. Use --ignore-garbage to attempt to recover
from any other non-alphabet bytes in the encoded stream. |
What does the command `shuf` do? | shuf - generate random permutations |
How is the `shuf` used? | shuf [OPTION]... [FILE]
shuf -e [OPTION]... [ARG]...
shuf -i LO-HI [OPTION]... |
What is the detailed desciption of the `shuf`? | Write a random permutation of the input lines to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-e, --echo
treat each ARG as an input line
-i, --input-range=LO-HI
treat each number LO through HI as an input line
-n, --head-count=COUNT
output at most COUNT lines
-o, --output=FILE
write result to FILE instead of standard output
--random-source=FILE
get random bytes from FILE
-r, --repeat
output lines can be repeated
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit |
What does the command `cut` do? | cut - remove sections from each line of files |
How is the `cut` used? | cut OPTION... [FILE]... |
What is the detailed desciption of the `cut`? | Print selected parts of lines from each FILE to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --bytes=LIST
select only these bytes
-c, --characters=LIST
select only these characters
-d, --delimiter=DELIM
use DELIM instead of TAB for field delimiter
-f, --fields=LIST
select only these fields; also print any line that contains no delimiter character, unless the -s option
is specified
-n (ignored)
--complement
complement the set of selected bytes, characters or fields
-s, --only-delimited
do not print lines not containing delimiters
--output-delimiter=STRING
use STRING as the output delimiter the default is to use the input delimiter
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit
Use one, and only one of -b, -c or -f. Each LIST is made up of one range, or many ranges separated by commas.
Selected input is written in the same order that it is read, and is written exactly once. Each range is one of:
N N'th byte, character or field, counted from 1
N- from N'th byte, character or field, to end of line
N-M from N'th to M'th (included) byte, character or field
-M from first to M'th (included) byte, character or field |
What does the command `paste` do? | paste - merge lines of files |
How is the `paste` used? | paste [OPTION]... [FILE]... |
What is the detailed desciption of the `paste`? | Write lines consisting of the sequentially corresponding lines from each FILE, separated by TABs, to standard
output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --delimiters=LIST
reuse characters from LIST instead of TABs
-s, --serial
paste one file at a time instead of in parallel
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit |
What does the command `ptx` do? | ptx - produce a permuted index of file contents |
How is the `ptx` used? | ptx [OPTION]... [INPUT]... (without -G)
ptx -G [OPTION]... [INPUT [OUTPUT]] |
What is the detailed desciption of the `ptx`? | Output a permuted index, including context, of the words in the input files.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-A, --auto-reference
output automatically generated references
-G, --traditional
behave more like System V 'ptx'
-F, --flag-truncation=STRING
use STRING for flagging line truncations. The default is '/'
-M, --macro-name=STRING
macro name to use instead of 'xx'
-O, --format=roff
generate output as roff directives
-R, --right-side-refs
put references at right, not counted in -w
-S, --sentence-regexp=REGEXP
for end of lines or end of sentences
-T, --format=tex
generate output as TeX directives
-W, --word-regexp=REGEXP
use REGEXP to match each keyword
-b, --break-file=FILE
word break characters in this FILE
-f, --ignore-case
fold lower case to upper case for sorting
-g, --gap-size=NUMBER
gap size in columns between output fields
-i, --ignore-file=FILE
read ignore word list from FILE
-o, --only-file=FILE
read only word list from this FILE
-r, --references
first field of each line is a reference
-t, --typeset-mode - not implemented -
-w, --width=NUMBER
output width in columns, reference excluded
--help display this help and exit
--version
output version information and exit |
What does the command `unexpand` do? | unexpand - convert spaces to tabs |
How is the `unexpand` used? | unexpand [OPTION]... [FILE]... |
What is the detailed desciption of the `unexpand`? | Convert blanks in each FILE to tabs, writing to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-a, --all
convert all blanks, instead of just initial blanks
--first-only
convert only leading sequences of blanks (overrides -a)
-t, --tabs=N
have tabs N characters apart instead of 8 (enables -a)
-t, --tabs=LIST
use comma separated list of tab positions. The last specified position can be prefixed with '/' to spec‐
ify a tab size to use after the last explicitly specified tab stop. Also a prefix of '+' can be used to
align remaining tab stops relative to the last specified tab stop instead of the first column
--help display this help and exit
--version
output version information and exit |
What does the command `sha1sum` do? | sha1sum - compute and check SHA1 message digest |
How is the `sha1sum` used? | sha1sum [OPTION]... [FILE]... |
What is the detailed desciption of the `sha1sum`? | Print or check SHA1 (160-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary
read in binary mode
-c, --check
read checksums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text
read in text mode (default)
-z, --zero
end each output line with NUL, not newline, and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing
don't fail or report status for missing files
--quiet
don't print OK for each successfully verified file
--status
don't output anything, status code shows success
--strict
exit non-zero for improperly formatted checksum lines
-w, --warn
warn about improperly formatted checksum lines
--help display this help and exit
--version
output version information and exit
The sums are computed as described in FIPS-180-1. When checking, the input should be a former output of this
program. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*'
for binary, ' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems. |
What does the command `test` do? | test - check file types and compare values |
How is the `test` used? | test EXPRESSION
test
[ EXPRESSION ]
[ ]
[ OPTION |
What is the detailed desciption of the `test`? | Exit with the status determined by EXPRESSION.
--help display this help and exit
--version
output version information and exit
An omitted EXPRESSION defaults to false. Otherwise, EXPRESSION is true or false and sets exit status. It is
one of:
( EXPRESSION )
EXPRESSION is true
! EXPRESSION
EXPRESSION is false
EXPRESSION1 -a EXPRESSION2
both EXPRESSION1 and EXPRESSION2 are true
EXPRESSION1 -o EXPRESSION2
either EXPRESSION1 or EXPRESSION2 is true
-n STRING
the length of STRING is nonzero
STRING equivalent to -n STRING
-z STRING
the length of STRING is zero
STRING1 = STRING2
the strings are equal
STRING1 != STRING2
the strings are not equal
INTEGER1 -eq INTEGER2
INTEGER1 is equal to INTEGER2
INTEGER1 -ge INTEGER2
INTEGER1 is greater than or equal to INTEGER2
INTEGER1 -gt INTEGER2
INTEGER1 is greater than INTEGER2
INTEGER1 -le INTEGER2
INTEGER1 is less than or equal to INTEGER2
INTEGER1 -lt INTEGER2
INTEGER1 is less than INTEGER2
INTEGER1 -ne INTEGER2
INTEGER1 is not equal to INTEGER2
FILE1 -ef FILE2
FILE1 and FILE2 have the same device and inode numbers
FILE1 -nt FILE2
FILE1 is newer (modification date) than FILE2
FILE1 -ot FILE2
FILE1 is older than FILE2
-b FILE
FILE exists and is block special
-c FILE
FILE exists and is character special
-d FILE
FILE exists and is a directory
-e FILE
FILE exists
-f FILE
FILE exists and is a regular file
-g FILE
FILE exists and is set-group-ID
-G FILE
FILE exists and is owned by the effective group ID
-h FILE
FILE exists and is a symbolic link (same as -L)
-k FILE
FILE exists and has its sticky bit set
-L FILE
FILE exists and is a symbolic link (same as -h)
-N FILE
FILE exists and has been modified since it was last read
-O FILE
FILE exists and is owned by the effective user ID
-p FILE
FILE exists and is a named pipe
-r FILE
FILE exists and the user has read access
-s FILE
FILE exists and has a size greater than zero
-S FILE
FILE exists and is a socket
-t FD file descriptor FD is opened on a terminal
-u FILE
FILE exists and its set-user-ID bit is set
-w FILE
FILE exists and the user has write access
-x FILE
FILE exists and the user has execute (or search) access
Except for -h and -L, all FILE-related tests dereference symbolic links. Beware that parentheses need to be es‐
caped (e.g., by backslashes) for shells. INTEGER may also be -l STRING, which evaluates to the length of
STRING.
NOTE: Binary -a and -o are inherently ambiguous. Use 'test EXPR1 && test EXPR2' or 'test EXPR1 || test EXPR2'
instead.
NOTE: [ honors the --help and --version options, but test does not. test treats each of those as it treats any
other nonempty STRING.
NOTE: your shell may have its own version of test and/or [, which usually supersedes the version described here.
Please refer to your shell's documentation for details about the options it supports. |
What does the command `tsort` do? | tsort - perform topological sort |
How is the `tsort` used? | tsort [OPTION] [FILE] |
What is the detailed desciption of the `tsort`? | Write totally ordered list consistent with the partial ordering in FILE.
With no FILE, or when FILE is -, read standard input.
--help display this help and exit
--version
output version information and exit |
What does the command `pathchk` do? | pathchk - check whether file names are valid or portable |
How is the `pathchk` used? | pathchk [OPTION]... NAME... |
What is the detailed desciption of the `pathchk`? | Diagnose invalid or non-portable file names.
-p check for most POSIX systems
-P check for empty names and leading "-"
--portability
check for all POSIX systems (equivalent to -p -P)
--help display this help and exit
--version
output version information and exit |
What does the command `od` do? | od - dump files in octal and other formats |
How is the `od` used? | od [OPTION]... [FILE]...
od [-abcdfilosx]... [FILE] [[+]OFFSET[.][b]]
od --traditional [OPTION]... [FILE] [[+]OFFSET[.][b] [+][LABEL][.][b]] |
What is the detailed desciption of the `od`? | Write an unambiguous representation, octal bytes by default, of FILE to standard output. With more than one
FILE argument, concatenate them in the listed order to form the input.
With no FILE, or when FILE is -, read standard input.
If first and second call formats both apply, the second format is assumed if the last operand begins with + or
(if there are 2 operands) a digit. An OFFSET operand means -j OFFSET. LABEL is the pseudo-address at first
byte printed, incremented when dump is progressing. For OFFSET and LABEL, a 0x or 0X prefix indicates hexadeci‐
mal; suffixes may be . for octal and b for multiply by 512.
Mandatory arguments to long options are mandatory for short options too.
-A, --address-radix=RADIX
output format for file offsets; RADIX is one of [doxn], for Decimal, Octal, Hex or None
--endian={big|little}
swap input bytes according the specified order
-j, --skip-bytes=BYTES
skip BYTES input bytes first
-N, --read-bytes=BYTES
limit dump to BYTES input bytes
-S BYTES, --strings[=BYTES]
show only NUL terminated strings of at least BYTES (3) printable characters
-t, --format=TYPE
select output format or formats
-v, --output-duplicates
do not use * to mark line suppression
-w[BYTES], --width[=BYTES]
output BYTES bytes per output line; 32 is implied when BYTES is not specified
--traditional
accept arguments in third form above
--help display this help and exit
--version
output version information and exit
Traditional format specifications may be intermixed; they accumulate:
-a same as -t a, select named characters, ignoring high-order bit
-b same as -t o1, select octal bytes
-c same as -t c, select printable characters or backslash escapes
-d same as -t u2, select unsigned decimal 2-byte units
-f same as -t fF, select floats
-i same as -t dI, select decimal ints
-l same as -t dL, select decimal longs
-o same as -t o2, select octal 2-byte units
-s same as -t d2, select decimal 2-byte units
-x same as -t x2, select hexadecimal 2-byte units
TYPE is made up of one or more of these specifications:
a named character, ignoring high-order bit
c printable character or backslash escape
d[SIZE]
signed decimal, SIZE bytes per integer
f[SIZE]
floating point, SIZE bytes per float
o[SIZE]
octal, SIZE bytes per integer
u[SIZE]
unsigned decimal, SIZE bytes per integer
x[SIZE]
hexadecimal, SIZE bytes per integer
SIZE is a number. For TYPE in [doux], SIZE may also be C for sizeof(char), S for sizeof(short), I for
sizeof(int) or L for sizeof(long). If TYPE is f, SIZE may also be F for sizeof(float), D for sizeof(double) or
L for sizeof(long double).
Adding a z suffix to any type displays printable characters at the end of each output line.
BYTES is hex with 0x or 0X prefix, and may have a multiplier suffix:
b 512
KB 1000
K 1024
MB 1000*1000
M 1024*1024
and so on for G, T, P, E, Z, Y, R, Q. Binary prefixes can be used, too: KiB=K, MiB=M, and so on. |
What does the command `link` do? | link - call the link function to create a link to a file |
How is the `link` used? | link FILE1 FILE2
link OPTION |
What is the detailed desciption of the `link`? | Call the link function to create a link named FILE2 to an existing FILE1.
--help display this help and exit
--version
output version information and exit |
What does the command `tee` do? | tee - read from standard input and write to standard output and files |
How is the `tee` used? | tee [OPTION]... [FILE]... |
What is the detailed desciption of the `tee`? | Copy standard input to each FILE, and also to standard output.
-a, --append
append to the given FILEs, do not overwrite
-i, --ignore-interrupts
ignore interrupt signals
-p operate in a more appropriate MODE with pipes.
--output-error[=MODE]
set behavior on write error. See MODE below
--help display this help and exit
--version
output version information and exit
MODE determines behavior with write errors on the outputs:
warn diagnose errors writing to any output
warn-nopipe
diagnose errors writing to any output not a pipe
exit exit on error writing to any output
exit-nopipe
exit on error writing to any output not a pipe
The default MODE for the -p option is 'warn-nopipe'. With "nopipe" MODEs, exit immediately if all outputs be‐
come broken pipes. The default operation when --output-error is not specified, is to exit immediately on error
writing to a pipe, and diagnose errors writing to non pipe outputs. |
What does the command `cksum` do? | cksum - compute and verify file checksums |
How is the `cksum` used? | cksum [OPTION]... [FILE]... |
What is the detailed desciption of the `cksum`? | Print or verify checksums. By default use the 32 bit CRC algorithm.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-a, --algorithm=TYPE
select the digest type to use. See DIGEST below.
--base64
emit base64-encoded digests, not hexadecimal
-c, --check
read checksums from the FILEs and check them
-l, --length=BITS
digest length in bits; must not exceed the max for the blake2 algorithm and must be a multiple of 8
--raw emit a raw binary digest, not hexadecimal
--tag create a BSD-style checksum (the default)
--untagged
create a reversed style checksum, without digest type
-z, --zero
end each output line with NUL, not newline, and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing
don't fail or report status for missing files
--quiet
don't print OK for each successfully verified file
--status
don't output anything, status code shows success
--strict
exit non-zero for improperly formatted checksum lines
-w, --warn
warn about improperly formatted checksum lines
--debug
indicate which implementation used
--help display this help and exit
--version
output version information and exit
DIGEST determines the digest algorithm and default output format:
sysv (equivalent to sum -s)
bsd (equivalent to sum -r)
crc (equivalent to cksum)
md5 (equivalent to md5sum)
sha1 (equivalent to sha1sum)
sha224 (equivalent to sha224sum)
sha256 (equivalent to sha256sum)
sha384 (equivalent to sha384sum)
sha512 (equivalent to sha512sum)
blake2b
(equivalent to b2sum)
sm3 (only available through cksum)
When checking, the input should be a former output of this program, or equivalent standalone program. |
What does the command `timeout` do? | timeout - run a command with a time limit |
How is the `timeout` used? | timeout [OPTION] DURATION COMMAND [ARG]...
timeout [OPTION] |
What is the detailed desciption of the `timeout`? | Start COMMAND, and kill it if still running after DURATION.
Mandatory arguments to long options are mandatory for short options too.
--preserve-status
exit with the same status as COMMAND, even when the
command times out
--foreground
when not running timeout directly from a shell prompt,
allow COMMAND to read from the TTY and get TTY signals; in this mode, children of COMMAND will not be
timed out
-k, --kill-after=DURATION
also send a KILL signal if COMMAND is still running
this long after the initial signal was sent
-s, --signal=SIGNAL
specify the signal to be sent on timeout;
SIGNAL may be a name like 'HUP' or a number; see 'kill -l' for a list of signals
-v, --verbose
diagnose to stderr any signal sent upon timeout
--help display this help and exit
--version
output version information and exit
DURATION is a floating point number with an optional suffix: 's' for seconds (the default), 'm' for minutes, 'h'
for hours or 'd' for days. A duration of 0 disables the associated timeout.
Upon timeout, send the TERM signal to COMMAND, if no other SIGNAL specified. The TERM signal kills any process
that does not block or catch that signal. It may be necessary to use the KILL signal, since this signal can't
be caught.
Exit status:
124 if COMMAND times out, and --preserve-status is not specified
125 if the timeout command itself fails
126 if COMMAND is found but cannot be invoked
127 if COMMAND cannot be found
137 if COMMAND (or timeout itself) is sent the KILL (9) signal (128+9)
- the exit status of COMMAND otherwise |
What does the command `factor` do? | factor - factor numbers |
How is the `factor` used? | factor [OPTION] [NUMBER]... |
What is the detailed desciption of the `factor`? | Print the prime factors of each specified integer NUMBER. If none are specified on the command line, read them
from standard input.
-h, --exponents
print repeated factors in form p^e unless e is 1
--help display this help and exit
--version
output version information and exit |
What does the command `df` do? | df - report file system space usage |
How is the `df` used? | df [OPTION]... [FILE]... |
What is the detailed desciption of the `df`? | This manual page documents the GNU version of df. df displays the amount of space
available on the file system containing each file name argument. If no file name is
given, the space available on all currently mounted file systems is shown. Space is
shown in 1K blocks by default, unless the environment variable POSIXLY_CORRECT is
set, in which case 512-byte blocks are used.
If an argument is the absolute file name of a device node containing a mounted file
system, df shows the space available on that file system rather than on the file
system containing the device node. This version of df cannot show the space avail‐
able on unmounted file systems, because on most kinds of systems doing so requires
non-portable intimate knowledge of file system structures. |
What does the command `cp` do? | cp - copy files and directories |
How is the `cp` used? | cp [OPTION]... [-T] SOURCE DEST
cp [OPTION]... SOURCE... DIRECTORY
cp [OPTION]... -t DIRECTORY SOURCE... |
What is the detailed desciption of the `cp`? | Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
Mandatory arguments to long options are mandatory for short options too.
-a, --archive
same as -dR --preserve=all
--attributes-only
don't copy the file data, just the attributes
--backup[=CONTROL]
make a backup of each existing destination file
-b like --backup but does not accept an argument
--copy-contents
copy contents of special files when recursive
-d same as --no-dereference --preserve=links
--debug
explain how a file is copied. Implies -v
-f, --force
if an existing destination file cannot be opened, remove it and try again
(this option is ignored when the -n option is also used)
-i, --interactive
prompt before overwrite (overrides a previous -n option)
-H follow command-line symbolic links in SOURCE
-l, --link
hard link files instead of copying
-L, --dereference
always follow symbolic links in SOURCE
-n, --no-clobber
do not overwrite an existing file and do not fail (overrides a -u or previous
-i option). See also --update; equivalent to --update=none.
-P, --no-dereference
never follow symbolic links in SOURCE
-p same as --preserve=mode,ownership,timestamps
--preserve[=ATTR_LIST]
preserve the specified attributes
--no-preserve=ATTR_LIST
don't preserve the specified attributes
--parents
use full source file name under DIRECTORY
-R, -r, --recursive
copy directories recursively
--reflink[=WHEN]
control clone/CoW copies. See below
--remove-destination
remove each existing destination file before attempting to open it (contrast
with --force)
--sparse=WHEN
control creation of sparse files. See below
--strip-trailing-slashes
remove any trailing slashes from each SOURCE argument
-s, --symbolic-link
make symbolic links instead of copying
-S, --suffix=SUFFIX
override the usual backup suffix
-t, --target-directory=DIRECTORY
copy all SOURCE arguments into DIRECTORY
-T, --no-target-directory
treat DEST as a normal file
--update[=UPDATE]
control which existing files are updated; UPDATE={all,none,older(default)}.
See below
-u equivalent to --update[=older]
-v, --verbose
explain what is being done
-x, --one-file-system
stay on this file system
-Z set SELinux security context of destination file to default type
--context[=CTX]
like -Z, or if CTX is specified then set the SELinux or SMACK security con‐
text to CTX
--help display this help and exit
--version
output version information and exit
ATTR_LIST is a comma-separated list of attributes. Attributes are 'mode' for permis‐
sions (including any ACL and xattr permissions), 'ownership' for user and group,
'timestamps' for file timestamps, 'links' for hard links, 'context' for security
context, 'xattr' for extended attributes, and 'all' for all attributes.
By default, sparse SOURCE files are detected by a crude heuristic and the corre‐
sponding DEST file is made sparse as well. That is the behavior selected by
--sparse=auto. Specify --sparse=always to create a sparse DEST file whenever the
SOURCE file contains a long enough sequence of zero bytes. Use --sparse=never to
inhibit creation of sparse files.
UPDATE controls which existing files in the destination are replaced. 'all' is the
default operation when an --update option is not specified, and results in all ex‐
isting files in the destination being replaced. 'none' is similar to the --no-clob‐
ber option, in that no files in the destination are replaced, but also skipped files
do not induce a failure. 'older' is the default operation when --update is speci‐
fied, and results in files being replaced if they're older than the corresponding
source file.
When --reflink[=always] is specified, perform a lightweight copy, where the data
blocks are copied only when modified. If this is not possible the copy fails, or if
--reflink=auto is specified, fall back to a standard copy. Use --reflink=never to
ensure a standard copy is performed.
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX. The
version control method may be selected via the --backup option or through the VER‐
SION_CONTROL environment variable. Here are the values:
none, off
never make backups (even if --backup is given)
numbered, t
make numbered backups
existing, nil
numbered if numbered backups exist, simple otherwise
simple, never
always make simple backups
As a special case, cp makes a backup of SOURCE when the force and backup options are
given and SOURCE and DEST are the same name for an existing, regular file. |
What does the command `join` do? | join - join lines of two files on a common field |
How is the `join` used? | join [OPTION]... FILE1 FILE2 |
What is the detailed desciption of the `join`? | For each pair of input lines with identical join fields, write a line to standard output. The default join
field is the first, delimited by blanks.
When FILE1 or FILE2 (not both) is -, read standard input.
-a FILENUM
also print unpairable lines from file FILENUM, where FILENUM is 1 or 2, corresponding to FILE1 or FILE2
-e STRING
replace missing (empty) input fields with STRING; I.e., missing fields specified with '-12jo' options
-i, --ignore-case
ignore differences in case when comparing fields
-j FIELD
equivalent to '-1 FIELD -2 FIELD'
-o FORMAT
obey FORMAT while constructing output line
-t CHAR
use CHAR as input and output field separator
-v FILENUM
like -a FILENUM, but suppress joined output lines
-1 FIELD
join on this FIELD of file 1
-2 FIELD
join on this FIELD of file 2
--check-order
check that the input is correctly sorted, even if all input lines are pairable
--nocheck-order
do not check that the input is correctly sorted
--header
treat the first line in each file as field headers, print them without trying to pair them
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit
Unless -t CHAR is given, leading blanks separate fields and are ignored, else fields are separated by CHAR. Any
FIELD is a field number counted from 1. FORMAT is one or more comma or blank separated specifications, each be‐
ing 'FILENUM.FIELD' or '0'. Default FORMAT outputs the join field, the remaining fields from FILE1, the remain‐
ing fields from FILE2, all separated by CHAR. If FORMAT is the keyword 'auto', then the first line of each file
determines the number of fields output for each line.
Important: FILE1 and FILE2 must be sorted on the join fields. E.g., use "sort -k 1b,1" if 'join' has no op‐
tions, or use "join -t ''" if 'sort' has no options. Note, comparisons honor the rules specified by 'LC_COL‐
LATE'. If the input is not sorted and some lines cannot be joined, a warning message will be given. |
What does the command `sha256sum` do? | sha256sum - compute and check SHA256 message digest |
How is the `sha256sum` used? | sha256sum [OPTION]... [FILE]... |
What is the detailed desciption of the `sha256sum`? | Print or check SHA256 (256-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary
read in binary mode
-c, --check
read checksums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text
read in text mode (default)
-z, --zero
end each output line with NUL, not newline, and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing
don't fail or report status for missing files
--quiet
don't print OK for each successfully verified file
--status
don't output anything, status code shows success
--strict
exit non-zero for improperly formatted checksum lines
-w, --warn
warn about improperly formatted checksum lines
--help display this help and exit
--version
output version information and exit
The sums are computed as described in FIPS-180-2. When checking, the input should be a former output of this
program. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*'
for binary, ' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems. |
What does the command `uniq` do? | uniq - report or omit repeated lines |
How is the `uniq` used? | uniq [OPTION]... [INPUT [OUTPUT]] |
What is the detailed desciption of the `uniq`? | Filter adjacent matching lines from INPUT (or standard input), writing to OUTPUT (or standard output).
With no options, matching lines are merged to the first occurrence.
Mandatory arguments to long options are mandatory for short options too.
-c, --count
prefix lines by the number of occurrences
-d, --repeated
only print duplicate lines, one for each group
-D print all duplicate lines
--all-repeated[=METHOD]
like -D, but allow separating groups with an empty line; METHOD={none(default),prepend,separate}
-f, --skip-fields=N
avoid comparing the first N fields
--group[=METHOD]
show all items, separating groups with an empty line; METHOD={separate(default),prepend,append,both}
-i, --ignore-case
ignore differences in case when comparing
-s, --skip-chars=N
avoid comparing the first N characters
-u, --unique
only print unique lines
-z, --zero-terminated
line delimiter is NUL, not newline
-w, --check-chars=N
compare no more than N characters in lines
--help display this help and exit
--version
output version information and exit
A field is a run of blanks (usually spaces and/or TABs), then non-blank characters. Fields are skipped before
chars.
Note: 'uniq' does not detect repeated lines unless they are adjacent. You may want to sort the input first, or
use 'sort -u' without 'uniq'. |
What does the command `sha512sum` do? | sha512sum - compute and check SHA512 message digest |
How is the `sha512sum` used? | sha512sum [OPTION]... [FILE]... |
What is the detailed desciption of the `sha512sum`? | Print or check SHA512 (512-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary
read in binary mode
-c, --check
read checksums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text
read in text mode (default)
-z, --zero
end each output line with NUL, not newline, and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing
don't fail or report status for missing files
--quiet
don't print OK for each successfully verified file
--status
don't output anything, status code shows success
--strict
exit non-zero for improperly formatted checksum lines
-w, --warn
warn about improperly formatted checksum lines
--help display this help and exit
--version
output version information and exit
The sums are computed as described in FIPS-180-2. When checking, the input should be a former output of this
program. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*'
for binary, ' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems. |
What does the command `base32` do? | base32 - base32 encode/decode data and print to standard output |
How is the `base32` used? | base32 [OPTION]... [FILE] |
What is the detailed desciption of the `base32`? | Base32 encode or decode FILE, or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --decode
decode data
-i, --ignore-garbage
when decoding, ignore non-alphabet characters
-w, --wrap=COLS
wrap encoded lines after COLS character (default 76). Use 0 to disable line wrapping
--help display this help and exit
--version
output version information and exit
The data are encoded as described for the base32 alphabet in RFC 4648. When decoding, the input may contain
newlines in addition to the bytes of the formal base32 alphabet. Use --ignore-garbage to attempt to recover
from any other non-alphabet bytes in the encoded stream. |
What does the command `dirname` do? | dirname - strip last component from file name |
How is the `dirname` used? | dirname [OPTION] NAME... |
What is the detailed desciption of the `dirname`? | Output each NAME with its last non-slash component and trailing slashes removed; if NAME contains no /'s, output
'.' (meaning the current directory).
-z, --zero
end each output line with NUL, not newline
--help display this help and exit
--version
output version information and exit |
What does the command `numfmt` do? | numfmt - Convert numbers from/to human-readable strings |
How is the `numfmt` used? | numfmt [OPTION]... [NUMBER]... |
What is the detailed desciption of the `numfmt`? | Reformat NUMBER(s), or the numbers from standard input if none are specified.
Mandatory arguments to long options are mandatory for short options too.
--debug
print warnings about invalid input
-d, --delimiter=X
use X instead of whitespace for field delimiter
--field=FIELDS
replace the numbers in these input fields (default=1); see FIELDS below
--format=FORMAT
use printf style floating-point FORMAT; see FORMAT below for details
--from=UNIT
auto-scale input numbers to UNITs; default is 'none'; see UNIT below
--from-unit=N
specify the input unit size (instead of the default 1)
--grouping
use locale-defined grouping of digits, e.g. 1,000,000 (which means it has no effect in the C/POSIX lo‐
cale)
--header[=N]
print (without converting) the first N header lines; N defaults to 1 if not specified
--invalid=MODE
failure mode for invalid numbers: MODE can be: abort (default), fail, warn, ignore
--padding=N
pad the output to N characters; positive N will right-align; negative N will left-align; padding is ig‐
nored if the output is wider than N; the default is to automatically pad if a whitespace is found
--round=METHOD
use METHOD for rounding when scaling; METHOD can be: up, down, from-zero (default), towards-zero, nearest
--suffix=SUFFIX
add SUFFIX to output numbers, and accept optional SUFFIX in input numbers
--to=UNIT
auto-scale output numbers to UNITs; see UNIT below
--to-unit=N
the output unit size (instead of the default 1)
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit
UNIT options:
none no auto-scaling is done; suffixes will trigger an error
auto accept optional single/two letter suffix:
1K = 1000, 1Ki = 1024, 1M = 1000000, 1Mi = 1048576,
si accept optional single letter suffix:
1K = 1000, 1M = 1000000, ...
iec accept optional single letter suffix:
1K = 1024, 1M = 1048576, ...
iec-i accept optional two-letter suffix:
1Ki = 1024, 1Mi = 1048576, ...
FIELDS supports cut(1) style field ranges:
N N'th field, counted from 1
N- from N'th field, to end of line
N-M from N'th to M'th field (inclusive)
-M from first to M'th field (inclusive)
- all fields
Multiple fields/ranges can be separated with commas
FORMAT must be suitable for printing one floating-point argument '%f'. Optional quote (%'f) will enable
--grouping (if supported by current locale). Optional width value (%10f) will pad output. Optional zero (%010f)
width will zero pad the number. Optional negative values (%-10f) will left align. Optional precision (%.1f)
will override the input determined precision.
Exit status is 0 if all input numbers were successfully converted. By default, numfmt will stop at the first
conversion error with exit status 2. With --invalid='fail' a warning is printed for each conversion error and
the exit status is 2. With --invalid='warn' each conversion error is diagnosed, but the exit status is 0. With
--invalid='ignore' conversion errors are not diagnosed and the exit status is 0. |
What does the command `dir` do? | dir - list directory contents |
How is the `dir` used? | dir [OPTION]... [FILE]... |
What is the detailed desciption of the `dir`? | List information about the FILEs (the current directory by default). Sort entries
alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all
do not ignore entries starting with .
-A, --almost-all
do not list implied . and ..
--author
with -l, print the author of each file
-b, --escape
print C-style escapes for nongraphic characters
--block-size=SIZE
with -l, scale sizes by SIZE when printing them; e.g., '--block-size=M'; see
SIZE format below
-B, --ignore-backups
do not list implied entries ending with ~
-c with -lt: sort by, and show, ctime (time of last change of file status infor‐
mation); with -l: show ctime and sort by name; otherwise: sort by ctime,
newest first
-C list entries by columns
--color[=WHEN]
color the output WHEN; more info below
-d, --directory
list directories themselves, not their contents
-D, --dired
generate output designed for Emacs' dired mode
-f list all entries in directory order
-F, --classify[=WHEN]
append indicator (one of */=>@|) to entries WHEN
--file-type
likewise, except do not append '*'
--format=WORD
across -x, commas -m, horizontal -x, long -l, single-column -1, verbose -l,
vertical -C
--full-time
like -l --time-style=full-iso
-g like -l, but do not list owner
--group-directories-first
group directories before files; can be augmented with a --sort option, but
any use of --sort=none (-U) disables grouping
-G, --no-group
in a long listing, don't print group names
-h, --human-readable
with -l and -s, print sizes like 1K 234M 2G etc.
--si likewise, but use powers of 1000 not 1024
-H, --dereference-command-line
follow symbolic links listed on the command line
--dereference-command-line-symlink-to-dir
follow each command line symbolic link that points to a directory
--hide=PATTERN
do not list implied entries matching shell PATTERN (overridden by -a or -A)
--hyperlink[=WHEN]
hyperlink file names WHEN
--indicator-style=WORD
append indicator with style WORD to entry names: none (default), slash (-p),
file-type (--file-type), classify (-F)
-i, --inode
print the index number of each file
-I, --ignore=PATTERN
do not list implied entries matching shell PATTERN
-k, --kibibytes
default to 1024-byte blocks for file system usage; used only with -s and per
directory totals
-l use a long listing format
-L, --dereference
when showing file information for a symbolic link, show information for the
file the link references rather than for the link itself
-m fill width with a comma separated list of entries
-n, --numeric-uid-gid
like -l, but list numeric user and group IDs
-N, --literal
print entry names without quoting
-o like -l, but do not list group information
-p, --indicator-style=slash
append / indicator to directories
-q, --hide-control-chars
print ? instead of nongraphic characters
--show-control-chars
show nongraphic characters as-is (the default, unless program is 'ls' and
output is a terminal)
-Q, --quote-name
enclose entry names in double quotes
--quoting-style=WORD
use quoting style WORD for entry names: literal, locale, shell, shell-always,
shell-escape, shell-escape-always, c, escape (overrides QUOTING_STYLE envi‐
ronment variable)
-r, --reverse
reverse order while sorting
-R, --recursive
list subdirectories recursively
-s, --size
print the allocated size of each file, in blocks
-S sort by file size, largest first
--sort=WORD
sort by WORD instead of name: none (-U), size (-S), time (-t), version (-v),
extension (-X), width
--time=WORD
select which timestamp used to display or sort; access time (-u): atime, ac‐
cess, use; metadata change time (-c): ctime, status; modified time (default):
mtime, modification; birth time: birth, creation;
with -l, WORD determines which time to show; with --sort=time, sort by WORD
(newest first)
--time-style=TIME_STYLE
time/date format with -l; see TIME_STYLE below
-t sort by time, newest first; see --time
-T, --tabsize=COLS
assume tab stops at each COLS instead of 8
-u with -lt: sort by, and show, access time; with -l: show access time and sort
by name; otherwise: sort by access time, newest first
-U do not sort; list entries in directory order
-v natural sort of (version) numbers within text
-w, --width=COLS
set output width to COLS. 0 means no limit
-x list entries by lines instead of by columns
-X sort alphabetically by entry extension
-Z, --context
print any security context of each file
--zero end each output line with NUL, not newline
-1 list one file per line
--help display this help and exit
--version
output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units
are K,M,G,T,P,E,Z,Y,R,Q (powers of 1024) or KB,MB,... (powers of 1000). Binary pre‐
fixes can be used, too: KiB=K, MiB=M, and so on.
The TIME_STYLE argument can be full-iso, long-iso, iso, locale, or +FORMAT. FORMAT
is interpreted like in date(1). If FORMAT is FORMAT1<newline>FORMAT2, then FORMAT1
applies to non-recent files and FORMAT2 to recent files. TIME_STYLE prefixed with
'posix-' takes effect only outside the POSIX locale. Also the TIME_STYLE environ‐
ment variable sets the default style to use.
The WHEN argument defaults to 'always' and can also be 'auto' or 'never'.
Using color to distinguish file types is disabled both by default and with
--color=never. With --color=auto, ls emits color codes only when standard output is
connected to a terminal. The LS_COLORS environment variable can change the set‐
tings. Use the dircolors(1) command to set it.
Exit status:
0 if OK,
1 if minor problems (e.g., cannot access subdirectory),
2 if serious trouble (e.g., cannot access command-line argument). |
What does the command `groups` do? | groups - print the groups a user is in |
How is the `groups` used? | groups [OPTION]... [USERNAME]... |
What is the detailed desciption of the `groups`? | Print group memberships for each USERNAME or, if no USERNAME is specified, for the current process (which may
differ if the groups database has changed).
--help display this help and exit
--version
output version information and exit |
What does the command `printenv` do? | printenv - print all or part of environment |
How is the `printenv` used? | printenv [OPTION]... [VARIABLE]... |
What is the detailed desciption of the `printenv`? | Print the values of the specified environment VARIABLE(s). If no VARIABLE is specified, print name and value
pairs for them all.
-0, --null
end each output line with NUL, not newline
--help display this help and exit
--version
output version information and exit
NOTE: your shell may have its own version of printenv, which usually supersedes the version described here.
Please refer to your shell's documentation for details about the options it supports. |
What does the command `shred` do? | shred - overwrite a file to hide its contents, and optionally delete it |
How is the `shred` used? | shred [OPTION]... FILE... |
What is the detailed desciption of the `shred`? | Overwrite the specified FILE(s) repeatedly, in order to make it harder for even very expensive hardware probing
to recover the data.
If FILE is -, shred standard output.
Mandatory arguments to long options are mandatory for short options too.
-f, --force
change permissions to allow writing if necessary
-n, --iterations=N
overwrite N times instead of the default (3)
--random-source=FILE
get random bytes from FILE
-s, --size=N
shred this many bytes (suffixes like K, M, G accepted)
-u deallocate and remove file after overwriting
--remove[=HOW]
like -u but give control on HOW to delete; See below
-v, --verbose
show progress
-x, --exact
do not round file sizes up to the next full block;
this is the default for non-regular files
-z, --zero
add a final overwrite with zeros to hide shredding
--help display this help and exit
--version
output version information and exit
Delete FILE(s) if --remove (-u) is specified. The default is not to remove the files because it is common to
operate on device files like /dev/hda, and those files usually should not be removed. The optional HOW parame‐
ter indicates how to remove a directory entry: 'unlink' => use a standard unlink call. 'wipe' => also first ob‐
fuscate bytes in the name. 'wipesync' => also sync each obfuscated byte to the device. The default mode is
'wipesync', but note it can be expensive.
CAUTION: shred assumes the file system and hardware overwrite data in place. Although this is common, many
platforms operate otherwise. Also, backups and mirrors may contain unremovable copies that will let a shredded
file be recovered later. See the GNU coreutils manual for details. |
What does the command `du` do? | du - estimate file space usage |
How is the `du` used? | du [OPTION]... [FILE]...
du [OPTION]... --files0-from=F |
What is the detailed desciption of the `du`? | Summarize device usage of the set of FILEs, recursively for directories.
Mandatory arguments to long options are mandatory for short options too.
-0, --null
end each output line with NUL, not newline
-a, --all
write counts for all files, not just directories
--apparent-size
print apparent sizes rather than device usage; although the apparent size is usually smaller, it may be
larger due to holes in ('sparse') files, internal fragmentation, indirect blocks, and the like
-B, --block-size=SIZE
scale sizes by SIZE before printing them; e.g., '-BM' prints sizes in units of 1,048,576 bytes; see SIZE
format below
-b, --bytes
equivalent to '--apparent-size --block-size=1'
-c, --total
produce a grand total
-D, --dereference-args
dereference only symlinks that are listed on the command line
-d, --max-depth=N
print the total for a directory (or file, with --all) only if it is N or fewer levels below the command
line argument; --max-depth=0 is the same as --summarize
--files0-from=F
summarize device usage of the NUL-terminated file names specified in file F; if F is -, then read names
from standard input
-H equivalent to --dereference-args (-D)
-h, --human-readable
print sizes in human readable format (e.g., 1K 234M 2G)
--inodes
list inode usage information instead of block usage
-k like --block-size=1K
-L, --dereference
dereference all symbolic links
-l, --count-links
count sizes many times if hard linked
-m like --block-size=1M
-P, --no-dereference
don't follow any symbolic links (this is the default)
-S, --separate-dirs
for directories do not include size of subdirectories
--si like -h, but use powers of 1000 not 1024
-s, --summarize
display only a total for each argument
-t, --threshold=SIZE
exclude entries smaller than SIZE if positive, or entries greater than SIZE if negative
--time show time of the last modification of any file in the directory, or any of its subdirectories
--time=WORD
show time as WORD instead of modification time: atime, access, use, ctime or status
--time-style=STYLE
show times using STYLE, which can be: full-iso, long-iso, iso, or +FORMAT; FORMAT is interpreted like in
'date'
-X, --exclude-from=FILE
exclude files that match any pattern in FILE
--exclude=PATTERN
exclude files that match PATTERN
-x, --one-file-system
skip directories on different file systems
--help display this help and exit
--version
output version information and exit
Display values are in units of the first available SIZE from --block-size, and the DU_BLOCK_SIZE, BLOCK_SIZE and
BLOCKSIZE environment variables. Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).
The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y,R,Q
(powers of 1024) or KB,MB,... (powers of 1000). Binary prefixes can be used, too: KiB=K, MiB=M, and so on. |
What does the command `sha224sum` do? | sha224sum - compute and check SHA224 message digest |
How is the `sha224sum` used? | sha224sum [OPTION]... [FILE]... |
What is the detailed desciption of the `sha224sum`? | Print or check SHA224 (224-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary
read in binary mode
-c, --check
read checksums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text
read in text mode (default)
-z, --zero
end each output line with NUL, not newline, and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing
don't fail or report status for missing files
--quiet
don't print OK for each successfully verified file
--status
don't output anything, status code shows success
--strict
exit non-zero for improperly formatted checksum lines
-w, --warn
warn about improperly formatted checksum lines
--help display this help and exit
--version
output version information and exit
The sums are computed as described in RFC 3874. When checking, the input should be a former output of this pro‐
gram. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*' for
binary, ' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems. |
What does the command `chgrp` do? | chgrp - change group ownership |
How is the `chgrp` used? | chgrp [OPTION]... GROUP FILE...
chgrp [OPTION]... --reference=RFILE FILE... |
What is the detailed desciption of the `chgrp`? | Change the group of each FILE to GROUP. With --reference, change the group of each
FILE to that of RFILE.
-c, --changes
like verbose but report only when a change is made
-f, --silent, --quiet
suppress most error messages
-v, --verbose
output a diagnostic for every file processed
--dereference
affect the referent of each symbolic link (this is the default), rather than
the symbolic link itself
-h, --no-dereference
affect symbolic links instead of any referenced file (useful only on systems
that can change the ownership of a symlink)
--no-preserve-root
do not treat '/' specially (the default)
--preserve-root
fail to operate recursively on '/'
--reference=RFILE
use RFILE's group rather than specifying a GROUP. RFILE is always derefer‐
enced if a symbolic link.
-R, --recursive
operate on files and directories recursively
The following options modify how a hierarchy is traversed when the -R option is also
specified. If more than one is specified, only the final one takes effect.
-H if a command line argument is a symbolic link to a directory, traverse it
-L traverse every symbolic link to a directory encountered
-P do not traverse any symbolic links (default)
--help display this help and exit
--version
output version information and exit |
What does the command `touch` do? | touch - change file timestamps |
How is the `touch` used? | touch [OPTION]... FILE... |
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