Conditionals
| Operator |
Description |
| ! EXPRESSION |
The EXPRESSION is false. |
| -n STRING |
The length of STRING is greater than zero. |
| -z STRING |
The lengh of STRING is zero (ie it is empty). |
| STRING1 = STRING2 |
STRING1 is equal to STRING2 |
| STRING1 != STRING2 |
STRING1 is not equal to STRING2 |
| INTEGER1 -eq INTEGER2 |
INTEGER1 is numerically equal to INTEGER2 |
| INTEGER1 -ne INTEGER2 |
INTEGER1 is numerically not equal to INTEGER2 |
| INTEGER1 -gt INTEGER2 |
INTEGER1 is numerically greater than INTEGER2 |
| INTEGER1 -ge INTEGER2 |
INTEGER1 is numerically greater than or equal to INTEGER2 |
| INTEGER1 -lt INTEGER2 |
INTEGER1 is numerically less than INTEGER2 |
| INTEGER1 -le INTEGER2 |
INTEGER1 is numerically less than or equal to INTEGER2 |
| -d FILE |
FILE exists and is a directory. |
| -e FILE |
FILE exists. |
| -r FILE |
FILE exists and the read permission is granted. |
| -s FILE |
FILE exists and it’s size is greater than zero (ie. it is not empty). |
| -w FILE |
FILE exists and the write permission is granted. |
| -x FILE |
FILE exists and the execute permission is granted. |
if [ <some test> ]; then
<commands>
elif [ <some test> ]; then
<different commands>
else
<other commands>
fi
Reference