docs/docs/4.1/cmds/test.html
test [EXPRESSION][[EXPRESSION] ]
test checks the given conditions and sets the exit status to 0 if they are true, 1 if they are false.
The first form (test) is preferred. For compatibility with other shells, the second form is available: a matching pair of square brackets ([[EXPRESSION] ]).
When using a variable or command substitution as an argument with test you should almost always enclose it in double-quotes, as variables expanding to zero or more than one argument will most likely interact badly with test.
Warning
For historical reasons, test supports the one-argument form (test foo), and this will also be triggered by e.g. test -n $foo if $foo is unset. We recommend you don’t use the one-argument form and quote all variables or command substitutions used with test.
This confusing misfeature will be removed in future. test -n without any additional argument will be false, test -z will be true and any other invocation with exactly one or zero arguments, including test -d and test "foo" will be an error.
The same goes for [, e.g. ["foo"] and [-d] will be errors.
This can be turned on already via the test-require-arg feature flag, and will eventually become the default and then only option.
-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.
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.
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.
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.
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 \ (so they appear as \( and \)) to avoid being interpreted as a command substitution.
If the /tmp directory exists, copy the /etc/motd file to it:
if test -d /tmpcp /etc/motd /tmp/motdend
If the variable MANPATH is defined and not empty, print the contents. (If MANPATH is not defined, then it will expand to zero arguments, unless quoted.)
if test -n "$MANPATH"echo $MANPATHend
Be careful with unquoted variables:
if test -n $MANPATH# This will also be reached if $MANPATH is unset,# because in that case we have `test -n`, so it checks if "-n" is non-empty, and it is.echo $MANPATHend
This will change in a future release of fish, or already with the test-require-arg feature flag - if $MANPATH is unset, if test -n $MANPATH will be false.
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 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 executedend
A common comparison is with status:
if test $status -eq 0echo "Previous command succeeded"end
The previous test can likewise be inverted:
if test ! $status -eq 0echo "Previous command failed"end
which is logically equivalent to the following:
if test $status -ne 0echo "Previous command failed"end
Unlike many things in fish, test implements a subset of the IEEE Std 1003.1-2008 (POSIX.1) standard. The following exceptions apply:
The < and > operators for comparing strings are not implemented.
With test-require-arg, the zero- and one-argument modes will behave differently.
In cases such as this, one can use
commandtestto explicitly use the system’s standalonetestrather than thisbuiltintest.
Other commands that may be useful as a condition, and are often easier to use:
string - manipulate strings, which can do string operations including wildcard and regular expression matching
path - manipulate and check paths, which can do file checks and operations, including filters on multiple paths at once