|TEST(1)||FreeBSD General Commands Manual||TEST(1)|
NAMEtest, [ — condition evaluation utility
DESCRIPTIONThe test utility evaluates the expression and, if it evaluates to true, returns a zero (true) exit status; otherwise it returns 1 (false). If there is no expression, 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 retained for compatibility with previous versions of this program. 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.
- -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.
- -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.
- -G file
- True if file exists and its group matches the effective group id of this process.
- -S file
- True if file exists and is a socket.
- 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.
- 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 binary value of their characters.
- s1 > s2
- True if string s1 comes after s2 based on the binary value of their characters.
- 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.
If file is a symbolic link, test will fully dereference it and then evaluate the expression against the file referenced, except for the -h and -L primaries.
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.
The -a operator has higher precedence than the -o operator.
Some shells may provide a builtin test command which is similar or identical to this utility. Consult the builtin(1) manual page.
GRAMMAR AMBIGUITYThe test grammar is inherently ambiguous. In order to assure a degree of consistency, the cases described in the IEEE Std 1003.2 (“POSIX.2”), section D11.2/4.62.4, standard are evaluated consistently according to the rules specified in the standards document. All other cases are subject to the ambiguity in the command semantics.
In particular, only expressions containing -a, -o, ( or ) can be ambiguous.
EXIT STATUSThe test utility exits with one of the following values:
- expression evaluated to true.
- expression evaluated to false or expression was missing.
- An error occurred.
test FILE1 -nt FILE2using only POSIX functionality:
test -n "$(find -L -- FILE1 -prune -newer FILE2 2>/dev/null)"
This can be modified using non-standard find(1) primaries like -newerca to compare other timestamps.
COMPATIBILITYFor compatibility with some other implementations, the = primary can be substituted with == with the same meaning.
STANDARDSThe test utility implements a superset of the IEEE Std 1003.2 (“POSIX.2”) specification. The primaries <, ==, >, -ef, -nt, -ot, -G, and -O are extensions.
BUGSBoth sides are always evaluated in -a and -o. For instance, the writable status of file will be tested by the following command even though the former expression indicated false, which results in a gratuitous access to the file system:
To avoid this, write
[ -z abc -a -w file ]
[ -z abc ] && [ -w file ]
|June 1, 2013||FreeBSD|