NAME
test
, [
—
condition evaluation utility
SYNOPSIS
test |
expression |
[ |
expression ] |
DESCRIPTION
The test
utility evaluates the
expression and, if it evaluates to true, returns a
zero (true) exit status; otherwise it returns 1 (false). If no
expression is given, test
also
returns 1 (false). The form [
is an alias for
test
.
All operators and flags are separate arguments to the
test
utility. Symbolic links are followed for all
primaries except -h
and
-L
.
The following primaries are used to construct expression:
-b
file- True if file exists and is a block special file.
-c
file- True if file exists and is a character special file.
-d
file- True if file exists and is a directory.
-e
file- True if file exists (regardless of type).
-f
file- True if file exists and is a regular file.
-G
file- True if file exists and its group matches the effective group ID of this process.
-g
file- True if file exists and its set-group-ID flag is set.
-h
file- True if file exists and is a symbolic link.
-k
file- True if file exists and its sticky bit is set.
-L
file- True if file exists and is a symbolic link. This
operator is for compatibility purposes. Do not rely on its existence; use
-h
instead. -n
string- True if the length of string is nonzero.
-O
file- True if file exists and its owner matches the effective user ID of this process.
-p
file- True if file is a named pipe (FIFO).
-r
file- True if file exists and is readable.
-S
file- True if file exists and is a socket.
-s
file- True if file exists and has a size greater than zero.
-t
file_descriptor- True if the file whose file descriptor number is file_descriptor (default 1) is open and is associated with a terminal.
-u
file- True if file exists and its set-user-ID flag is set.
-w
file- True if file exists and is writable. True indicates only that the write flag is on. The file is not writable on a read-only file system even if this test indicates true.
-x
file- True if file exists and is executable. True indicates only that the execute flag is on. If file is a directory, true indicates that file can be searched.
-z
string- True if the length of string is zero.
- file1
-nt
file2 - True if file1 exists and is newer than file2.
- file1
-ot
file2 - True if file1 exists and is older than file2.
- file1
-ef
file2 - True if file1 and file2 exist and refer to the same file.
- s1
=
s2 - True if the strings s1 and s2 are identical.
- s1
!=
s2 - True if the strings s1 and s2 are not identical.
- s1
<
s2 - True if string s1 comes before s2 based on the ASCII value of their characters.
- s1
>
s2 - True if string s1 comes after s2 based on the ASCII value of their characters.
- s1
- True if s1 is not the null string.
- n1
-eq
n2 - True if the integers n1 and n2 are algebraically equal.
- n1
-ne
n2 - True if the integers n1 and n2 are not algebraically equal.
- n1
-gt
n2 - True if the integer n1 is algebraically greater than the integer n2.
- n1
-ge
n2 - True if the integer n1 is algebraically greater than or equal to the integer n2.
- n1
-lt
n2 - True if the integer n1 is algebraically less than the integer n2.
- n1
-le
n2 - True if the integer n1 is algebraically less than or equal to the integer n2.
These primaries can be combined with the following operators. The
-a
operator has higher precedence than the
-o
operator.
!
expression- True if expression is false.
- expression1
-a
expression2 - True if both expression1 and expression2 are true.
- expression1
-o
expression2 - True if either expression1 or expression2 are true.
(
expression)
- True if expression is true.
EXIT STATUS
The test
utility exits with one of the
following values:
- 0
- Expression evaluated to true.
- 1
- Expression evaluated to false or expression was missing.
- >1
- An error occurred.
GRAMMAR AMBIGUITY
The test
grammar is inherently ambiguous.
In order to assure a degree of consistency, the cases described in
IEEE Std 1003.2 (“POSIX.2”) section
D11.2/4.62.4 are evaluated consistently according to the rules specified in
the standards document. All other cases are subject to the ambiguity in the
command semantics.
SEE ALSO
STANDARDS
The test
utility is compliant with the
IEEE Std 1003.1-2008 (“POSIX.1”)
specification.
The primaries -G
,
-k
, -O
,
-nt
, -ot
,
-ef
, <
, and
>
are extensions to that specification.
The operators -a
,
-o
, and ()
are marked by
IEEE Std 1003.1-2008 (“POSIX.1”) as
part of X/Open System Interfaces and obsolete.
test
also exists as a built-in to
ksh(1), though with a different syntax.