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).
All operators and flags are separate arguments to the test utility.
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 set-group-ID flag is set.
- -h file
-
True if file exists and is a symbolic link. This operator is for COMPATABILITY purposes, do not rely on its existence. Use -L instead.
- -k file
-
True if file exists and its sticky bit is set.
- -n string
-
True if the length of string is nonzero.
- -p file
-
True if file is a named pipe (FIFO).
- -r file
-
True if file exists and is readable by the effective user/group.
- -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.
- -t
-
Same as above with an implicit file descriptor number of "1" (e.g.: -t 1).
- -u file
-
True if file exists and its set-user-ID flag is set.
- -w file
-
True if file exists and is writable by the effective user/group. 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 by the effective user/group. 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.
- -B file
-
True if file exists and is a binary file.
- -L file
-
True if file exists and is a symbolic link.
- -O file
-
True if file exists and its owner matches the effective user ID of this process.
- -R file
-
True if file exists and is readable by the real user/group.
- -S file
-
True if file exists and is a socket.
- -T file
-
True if file exists and is a text file.
- -W file
-
True if file exists and is writable by the real user/group. 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 by the real user/group. True indicates only that the execute flag is on. If file is a directory, true indicates that file can be searched.
- file1 -nt file2
-
True if file1 exists and is newer than file2.
- file1 -ot file2
-
True if file1 exists and is older than file2.
- string
-
True if string is not the null string.
- 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:
- ! 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 (uses parentheses for grouping).
Note that the -a operator has higher precedence than the -o operator. Notice also that all the operators and flags are separate arguments to test.
RETURN VALUES
The test utility exits with one of the following values:
- $return_val == 0
-
Expression evaluated to true.
- $return_val == 1
-
Expression evaluated to false or expression was missing.
- $return_val > 1
-
An error occurred.
CAVEATS
Command line arguments like parentheses and arithmetic operators (e.g.: '(', ')', '!', '>', '<', etc.) may be meaningful to the command-line interpreter (shell) and therefore may need to be escaped from any special shell interpretation.