B.5. Test Operators

Table B-6 lists the operators that are used with test and the [...] and [[...]] constructs. They can be logically combined with -a ("and") and -o ("or") and grouped with escaped parenthesis (\( ... \)). The string comparisons < and > and the [[...]] construct are not available in versions of bash prior to 2.0.

Table B-6. Test operators

Operator	True if...
-a file	file exists
-b file	file exists and is a block device file
-c file	file exists and is a character device file
-d file	file exists and is a directory
-e file	file exists; same as -a
-f file	file exists and is a regular file
-g file	file exists and has its setgid bit set
-G file	file exists and is owned by the effective group ID
-h file	file exists and is a symbolic link
-k file	file exists and has its sticky bit set
-L file	file exists and is a symbolic link
-n string	string is non-null
-N file	file was modified since it was last read
-O file	file exists and is owned by the effective user ID
-p file	file exists and is a pipe or named pipe (FIFO file)
-r file	file exists and is readable
-s file	file exists and is not empty
-S file	file exists and is a socket
-t N	File descriptor N points to a terminal
-u file	file exists and has its setuid bit set
-w file	file exists and is writeable
-x file	file exists and is executable, or file is a directory that can be searched
-z string	string has a length of zero
fileA -nt fileB	fileA modification time is newer than fileB
fileA -ot fileB	fileA modification time is older than fileB
fileA -ef fileB	fileA and fileB point to the same file
stringA = stringB	stringA equals stringB (POSIX version)
stringA == stringB	stringA equals stringB
stringA != stringB	stringA does not match stringB
stringA =~ regexp	stringA matches the extended regular expression regexp[3]
stringA < stringB	stringA sorts before stringB lexicographically
stringA > stringB	stringA sorts after stringB lexicographically
exprA -eq exprB	Arithmetic expressions exprA and exprB are equal
exprA -ne exprB	Arithmetic expressions exprA and exprB are not equal
exprA -lt exprB	exprA is less than exprB
exprA -gt exprB	exprA is greater than exprB
exprA -le exprB	exprA is less than or equal to exprB
exprA -ge exprB	exprA is greater than or equal to exprB
exprA -a exprB	exprA is true and exprB is true
exprA -o exprB	exprA is true or exprB is true

^[3] Only available in bash version 3.0 and later. May only be used inside [[...]].