mirror of
https://github.com/fish-shell/fish-shell.git
synced 2024-11-23 10:43:32 +08:00
251 lines
6.9 KiB
ReStructuredText
251 lines
6.9 KiB
ReStructuredText
.. _cmd-test:
|
|
|
|
test - perform tests on files and text
|
|
======================================
|
|
|
|
Synopsis
|
|
--------
|
|
|
|
.. synopsis::
|
|
|
|
test [EXPRESSION]
|
|
[ [EXPRESSION] ]
|
|
|
|
|
|
Description
|
|
-----------
|
|
|
|
.. only:: builder_man
|
|
|
|
NOTE: This page documents the fish builtin ``test``.
|
|
To see the documentation on the ``test`` command you might have,
|
|
use ``command man test``.
|
|
|
|
Tests the expression given and sets the exit status to 0 if true, and 1 if false. An expression is made up of one or more operators and their arguments.
|
|
|
|
The first form (``test``) is preferred. For compatibility with other shells, the second form is available: a matching pair of square brackets (``[ [EXPRESSION] ]``).
|
|
|
|
This test is mostly POSIX-compatible.
|
|
|
|
When using a variable as an argument for a test operator you should almost always enclose it in double-quotes. There are only two situations it is safe to omit the quote marks. The first is when the argument is a literal string with no whitespace or other characters special to the shell (e.g., semicolon). For example, ``test -b /my/file``. The second is using a variable that expands to exactly one element including if that element is the empty string (e.g., ``set x ''``). If the variable is not set, set but with no value, or set to more than one value you must enclose it in double-quotes. For example, ``test "$x" = "$y"``. Since it is always safe to enclose variables in double-quotes when used as ``test`` arguments that is the recommended practice.
|
|
|
|
Operators for files and directories
|
|
-----------------------------------
|
|
|
|
**-b** *FILE*
|
|
Returns true if *FILE* is a block device.
|
|
|
|
**-c** *FILE*
|
|
Returns true if *FILE* is a character device.
|
|
|
|
**-d** *FILE*
|
|
Returns true if *FILE* is a directory.
|
|
|
|
**-e** *FILE*
|
|
Returns true if *FILE* exists.
|
|
|
|
**-f** *FILE*
|
|
Returns true if *FILE* is a regular file.
|
|
|
|
**-g** *FILE*
|
|
Returns true if *FILE* has the set-group-ID bit set.
|
|
|
|
**-G** *FILE*
|
|
Returns true if *FILE* exists and has the same group ID as the current user.
|
|
|
|
**-k** *FILE*
|
|
Returns true if *FILE* has the sticky bit set. If the OS does not support the concept it returns false. See https://en.wikipedia.org/wiki/Sticky_bit.
|
|
|
|
**-L** *FILE*
|
|
Returns true if *FILE* is a symbolic link.
|
|
|
|
**-O** *FILE*
|
|
Returns true if *FILE* exists and is owned by the current user.
|
|
|
|
**-p** *FILE*
|
|
Returns true if *FILE* is a named pipe.
|
|
|
|
**-r** *FILE*
|
|
Returns true if *FILE* is marked as readable.
|
|
|
|
**-s** *FILE*
|
|
Returns true if the size of *FILE* is greater than zero.
|
|
|
|
**-S** *FILE*
|
|
Returns true if *FILE* is a socket.
|
|
|
|
**-t** *FD*
|
|
Returns true if the file descriptor *FD* is a terminal (TTY).
|
|
|
|
**-u** *FILE*
|
|
Returns true if *FILE* has the set-user-ID bit set.
|
|
|
|
**-w** *FILE*
|
|
Returns true if *FILE* is marked as writable; note that this does not check if the filesystem is read-only.
|
|
|
|
**-x** *FILE*
|
|
Returns true if *FILE* is marked as executable.
|
|
|
|
Operators to compare files and directories
|
|
------------------------------------------
|
|
|
|
*FILE1* **-nt** *FILE2*
|
|
Returns true if *FILE1* is newer than *FILE2*, or *FILE1* exists and *FILE2* does not.
|
|
|
|
*FILE1* **-ot** *FILE2*
|
|
Returns true if *FILE1* is older than *FILE2*, or *FILE2* exists and *FILE1* does not.
|
|
|
|
*FILE1* **-ef** *FILE1*
|
|
Returns true if *FILE1* and *FILE2* refer to the same file.
|
|
|
|
Operators for text strings
|
|
--------------------------
|
|
|
|
*STRING1* **=** *STRING2*
|
|
Returns true if the strings *STRING1* and *STRING2* are identical.
|
|
|
|
*STRING1* **!=** *STRING2*
|
|
Returns true if the strings *STRING1* and *STRING2* are not identical.
|
|
|
|
**-n** *STRING*
|
|
Returns true if the length of *STRING* is non-zero.
|
|
|
|
**-z** *STRING*
|
|
Returns true if the length of *STRING* is zero.
|
|
|
|
Operators to compare and examine numbers
|
|
----------------------------------------
|
|
|
|
*NUM1* **-eq** *NUM2*
|
|
Returns true if *NUM1* and *NUM2* are numerically equal.
|
|
|
|
*NUM1* **-ne** *NUM2*
|
|
Returns true if *NUM1* and *NUM2* are not numerically equal.
|
|
|
|
*NUM1* **-gt** *NUM2*
|
|
Returns true if *NUM1* is greater than *NUM2*.
|
|
|
|
*NUM1* **-ge** *NUM2*
|
|
Returns true if *NUM1* is greater than or equal to *NUM2*.
|
|
|
|
*NUM1* **-lt** *NUM2*
|
|
Returns true if *NUM1* is less than *NUM2*.
|
|
|
|
*NUM1* **-le** *NUM2*
|
|
Returns true if *NUM1* is less than or equal to *NUM2*.
|
|
|
|
Both integers and floating point numbers are supported.
|
|
|
|
Operators to combine expressions
|
|
--------------------------------
|
|
|
|
*COND1* **-a** *COND2*
|
|
Returns true if both *COND1* and *COND2* are true.
|
|
|
|
*COND1* **-o** *COND2*
|
|
Returns true if either *COND1* or *COND2* are true.
|
|
|
|
Expressions can be inverted using the **!** operator:
|
|
|
|
**!** *EXPRESSION*
|
|
Returns true if *EXPRESSION* is false, and false if *EXPRESSION* is true.
|
|
|
|
Expressions can be grouped using parentheses.
|
|
|
|
**(** *EXPRESSION* **)**
|
|
Returns the value of *EXPRESSION*.
|
|
|
|
Note that parentheses will usually require escaping with ``\(`` to avoid being interpreted as a command substitution.
|
|
|
|
|
|
Examples
|
|
--------
|
|
|
|
If the ``/tmp`` directory exists, copy the ``/etc/motd`` file to it:
|
|
|
|
|
|
|
|
::
|
|
|
|
if test -d /tmp
|
|
cp /etc/motd /tmp/motd
|
|
end
|
|
|
|
|
|
If the variable :envvar:`MANPATH` is defined and not empty, print the contents. (If :envvar:`MANPATH` is not defined, then it will expand to zero arguments, unless quoted.)
|
|
|
|
|
|
|
|
::
|
|
|
|
if test -n "$MANPATH"
|
|
echo $MANPATH
|
|
end
|
|
|
|
|
|
Parentheses and the ``-o`` and ``-a`` operators can be combined to produce more complicated expressions. In this example, success is printed if there is a ``/foo`` or ``/bar`` file as well as a ``/baz`` or ``/bat`` file.
|
|
|
|
|
|
|
|
::
|
|
|
|
if test \( -f /foo -o -f /bar \) -a \( -f /baz -o -f /bat \)
|
|
echo Success.
|
|
end
|
|
|
|
|
|
Numerical comparisons will simply fail if one of the operands is not a number:
|
|
|
|
|
|
|
|
::
|
|
|
|
if test 42 -eq "The answer to life, the universe and everything"
|
|
echo So long and thanks for all the fish # will not be executed
|
|
end
|
|
|
|
|
|
A common comparison is with :envvar:`status`:
|
|
|
|
|
|
|
|
::
|
|
|
|
if test $status -eq 0
|
|
echo "Previous command succeeded"
|
|
end
|
|
|
|
|
|
The previous test can likewise be inverted:
|
|
|
|
|
|
|
|
::
|
|
|
|
if test ! $status -eq 0
|
|
echo "Previous command failed"
|
|
end
|
|
|
|
|
|
which is logically equivalent to the following:
|
|
|
|
|
|
|
|
::
|
|
|
|
if test $status -ne 0
|
|
echo "Previous command failed"
|
|
end
|
|
|
|
|
|
Standards
|
|
---------
|
|
|
|
``test`` implements a subset of the `IEEE Std 1003.1-2008 (POSIX.1) standard <https://www.unix.com/man-page/posix/1p/test/>`__. The following exceptions apply:
|
|
|
|
- The ``<`` and ``>`` operators for comparing strings are not implemented.
|
|
|
|
- Because this test is a shell builtin and not a standalone utility, using the -c flag on a special file descriptors like standard input and output may not return the same result when invoked from within a pipe as one would expect when invoking the ``test`` utility in another shell.
|
|
|
|
In cases such as this, one can use ``command`` ``test`` to explicitly use the system's standalone ``test`` rather than this ``builtin`` ``test``.
|