test [EXPRESSION] [ [EXPRESSION] ]
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.
-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.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
.\(
to avoid being interpreted as a command substitution. 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 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 $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 $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
test
implements a subset of the IEEE Std 1003.1-2008 (POSIX.1) standard. The following exceptions apply:
<
and >
operators for comparing strings are not implemented.test
utility in another shell.command
test
to explicitly use the system's standalone test
rather than this builtin
test
.
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Licensed under the GNU General Public License, version 2.
https://fishshell.com/docs/3.1/cmds/test.html