search for files in a directory hierarchy
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find [-H] [-L] [-P] [-D debugopts] [-Olevel] [path...] [expression]
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-name pattern
Base of file name (the path with the leading directories removed) matches shell pattern pattern.
The metacharacters (`*', `?', and `[]') match a `.' at the start of the base name (this is a
change in findutils-4.2.2; see section STANDARDS CONFORMANCE below). To ignore a directory and
the files under it, use -prune; see an example in the description of -path. Braces are not
recognised as being special, despite the fact that some shells including Bash imbue braces with a
special meaning in shell patterns. The filename matching is performed with the use of the
fnmatch(3) library function. Don't forget to enclose the pattern in quotes in order to protect
it from expansion by the shell.
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-exec command ;
Execute command; true if 0 status is returned. All following arguments to find are taken to be
arguments to the command until an argument consisting of `;' is encountered. The string `{}' is
replaced by the current file name being processed everywhere it occurs in the arguments to the
command, not just in arguments where it is alone, as in some versions of find. Both of these
constructions might need to be escaped (with a `\') or quoted to protect them from expansion by
the shell. See the EXAMPLES section for examples of the use of the -exec option. The specified
command is run once for each matched file. The command is executed in the starting directory.
There are unavoidable security problems surrounding use of the -exec action; you should use the
-execdir option instead.
-exec command {} +
This variant of the -exec action runs the specified command on the selected files, but the command
line is built by appending each selected file name at the end; the total number of invocations of
the command will be much less than the number of matched files. The command line is built in much
the same way that xargs builds its command lines. Only one instance of `{}' is allowed within the
command. The command is executed in the starting directory.
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pattern scanning and processing language
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-F ERE
Define the input field separator to be the extended regular expression ERE, before any input is
read; see Regular Expressions .
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program
If no -f option is specified, the first operand to awk shall be the text of the awk program. The
application shall supply the program operand as a single argument to awk. If the text does not end
in a <newline>, awk shall interpret the text as if it did.
argument
Either of the following two types of argument can be intermixed:
file
A pathname of a file that contains the input to be read, which is matched against the set of
patterns in the program. If no file operands are specified, or if a file operand is '-' , the
standard input shall be used.
assignment
An operand that begins with an underscore or alphabetic character from the portable character set
(see the table in the Base Definitions volume of IEEE Std 1003.1-2001, Section 6.1, Portable
Character Set), followed by a sequence of underscores, digits, and alphabetics from the portable
character set, followed by the '=' character, shall specify a variable assignment rather than a
pathname. The characters before the '=' represent the name of an awk variable; if that name is an
awk reserved word (see Grammar ) the behavior is undefined. The characters following the equal
sign shall be interpreted as if they appeared in the awk program preceded and followed by a
double-quote ( ' )' character, as a STRING token (see Grammar ), except that if the last character
is an unescaped backslash, it shall be interpreted as a literal backslash rather than as the first
character of the sequence "\"" . The variable shall be assigned the value of that STRING token
and, if appropriate, shall be considered a numeric string (see Expressions in awk ), the variable
shall also be assigned its numeric value. Each such variable assignment shall occur just prior to
the processing of the following file, if any. Thus, an assignment before the first file argument
shall be executed after the BEGIN actions (if any), while an assignment after the last file
argument shall occur before the END actions (if any). If there are no file arguments, assignments
shall be executed before processing the standard input.
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Pipelines
A pipeline is a sequence of one or more commands separated by one of the control operators | or |&. The
format for a pipeline is:
[time [-p]] [ ! ] command [ [|⎪|&] command2 ... ]
The standard output of command is connected via a pipe to the standard input of command2. This
connection is performed before any redirections specified by the command (see REDIRECTION below). If |&
is used, the standard error of command is connected to command2's standard input through the pipe; it is
shorthand for 2>&1 |. This implicit redirection of the standard error is performed after any
redirections specified by the command.
The return status of a pipeline is the exit status of the last command, unless the pipefail option is
enabled. If pipefail is enabled, the pipeline's return status is the value of the last (rightmost)
command to exit with a non-zero status, or zero if all commands exit successfully. If the reserved word
! precedes a pipeline, the exit status of that pipeline is the logical negation of the exit status as
described above. The shell waits for all commands in the pipeline to terminate before returning a value.
If the time reserved word precedes a pipeline, the elapsed as well as user and system time consumed by
its execution are reported when the pipeline terminates. The -p option changes the output format to that
specified by POSIX. When the shell is in posix mode, it does not recognize time as a reserved word if
the next token begins with a `-'. The TIMEFORMAT variable may be set to a format string that specifies
how the timing information should be displayed; see the description of TIMEFORMAT under Shell Variables
below.
When the shell is in posix mode, time may be followed by a newline. In this case, the shell displays the
total user and system time consumed by the shell and its children. The TIMEFORMAT variable may be used
to specify the format of the time information.
Each command in a pipeline is executed as a separate process (i.e., in a subshell).
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sort, merge, or sequence check text files
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-u Unique: suppress all but one in each set of lines having equal keys. If used with the -c option,
check that there are no lines with duplicate keys, in addition to checking that the input file is
sorted.
The following options shall override the default ordering rules. When ordering options appear independent
of any key field specifications, the requested field ordering rules shall be applied globally to all sort
keys. When attached to a specific key (see -k), the specified ordering options shall override all global
ordering options for that key.
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Before a command is executed, its input and output may be redirected using a special notation interpreted
by the shell. Redirection may also be used to open and close files for the current shell execution
environment. The following redirection operators may precede or appear anywhere within a simple command
or may follow a command. Redirections are processed in the order they appear, from left to right.
Redirecting Output
Redirection of output causes the file whose name results from the expansion of word to be opened for
writing on file descriptor n, or the standard output (file descriptor 1) if n is not specified. If the
file does not exist it is created; if it does exist it is truncated to zero size.
The general format for redirecting output is:
[n]>word
If the redirection operator is >, and the noclobber option to the set builtin has been enabled, the
redirection will fail if the file whose name results from the expansion of word exists and is a regular
file. If the redirection operator is >|, or the redirection operator is > and the noclobber option to
the set builtin command is not enabled, the redirection is attempted even if the file named by word
exists.
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