Syntax
[[ -<option> <arg> ]] && echo 1 || echo 0
if [[ -<option> <arg> ]]; then
...
else
...
fi
Conditional Options for Values
-n string is not null
-z string is null, that is, has zero length
Conditional Options for File/Folder
| Option |
Description |
[ -b "$file" ] |
Return true if file is a block special file or else false |
[ -c "$file" ] |
Return true if file is a character special file or else false |
[ -d "$file" ] |
Return true if file is a directory or else false |
[ -f "$file" ] |
Return true if file is an ordinary file as opposed to a directory or special file or else false |
[ -g "$file" ] |
Checks if file has its set group ID (SGID) bit set or else false |
[ -k "$file" ] |
Checks if file has its sticky bit set or else false |
[ -p "$file" ] |
Return true if file is a named pipe or else false |
[ -t "$file" ] |
Checks if file descriptor is open and associated with a terminal or else false |
[ -u "$file" ] |
Return true if file has its Set User ID (SUID) bit set or else false |
[ -r "$file" ] |
Return true if file is readable or else false |
[ -w "$file" ] |
Return true if file is writable or else false |
[ -x "$file" ] |
Return true if file is executable or else false |
[ -s "$file" ] |
Return true if file has size greater than 0 or else false |
[ -e "$file" ] |
Return true if file exists or else false |
