Reference

test(1)

condition evaluation utility

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. Identical to -L.

-k file

True if file exists and its sticky bit is set.

-L file

True if file exists and is a symbolic link. Identical to -h.

-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 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

ksh(1)

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.

HISTORY

A test utility appeared in Version 7 AT&T UNIX.

History