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 |
