Name

test - check files and compare values

Synopsis

$ test expression
$ test
$ [ expression ]
$ [ ]

Description

test takes a given expression and sets the exit code according to its truthiness, 0 if true, 1 if false. An omitted expression defaults to false, and an unexpected error causes an exit code of 126.

If test is invoked as [, a trailing ] is required after the expression.

Expressions

The expression can take any of the following forms:

Grouping

• ( <expression> ) value of expression

Boolean operations

• ! <expression> negation of expression
• <expression> -a <expression> boolean conjunction of the values
• <expression> -o <expression> boolean disjunction of the values

String comparison

• <string> whether the string is non-empty
• -n <string> whether the string is non-empty
• -z <string> whether the string is empty
• <string> = <string> whether the two strings are equal
• <string> != <string> whether the two strings not equal

Integer comparison

• <integer> -eq <integer> whether the two integers are equal
• <integer> -ne <integer> whether the two integers are not equal
• <integer> -lt <integer> whether the integer on the left is less than the integer on the right
• <integer> -gt <integer> whether the integer on the left is greater than the integer on the right
• <integer> -le <integer> whether the integer on the left is less than or equal to the integer on the right
• <integer> -ge <integer> whether the integer on the left is greater than or equal to the integer on the right

File comparison

• <file> -ef <file> whether the two files are the same (have the same inode and device numbers)
• <file> -nt <file> whether the file on the left is newer than the file on the right (modification date is used)
• <file> -ot <file> whether the file on the left is older than the file on the right (modification date is used)

File type checks

• -b <file> whether the file is a block device
• -c <file> whether the file is a character device
• -f <file> whether the file is a regular file
• -d <file> whether the file is a directory
• -p <file> whether the file is a pipe
• -S <file> whether the file is a socket
• -h <file>, -L <file> whether the file is a symbolic link

File permission checks

• -r <file> whether the current user has read access to the file
• -w <file> whether the current user has write access to the file
• -x <file> whether the current user has execute access to the file
• -e <file> whether the file exists

Except for -h/-L, all file checks dereference symbolic links.

NOTE: Your shell might have a builtin named 'test' and/or '[', please refer to your shell's documentation for further details.

Options

None.

Examples

# Conditionally do something based on the value of a variable
$ /bin/test "$foo" = bar && echo foo is bar
# Check some numbers
$ /bin/test \( 10 -gt 20 \) -o \( ! 10 -ne 10 \) && echo "magic numbers!"

See Also

• find(1)