| Command | Function |
|---|---|
| #!/bin/bash or #!/bin/sh | shebang |
| VAR=var | set VAR to var |
| $VAR | inserts var whereever $VAR is placed |
| case - esac | inserts case |
| if [ “var” == “var” ]; then fi | inserts if |
| Operator | Description |
|---|---|
| -eq | Returns true if two numbers are equivalent |
| -lt | Returns true if a number is less than another number |
| -gt | Returns true if a number is greater than another number |
| == | Returns true if two strings are equivalent |
| != | Returns true if two strings are not equivalent |
| ! | Returns true if the expression is false |
| -d | Check the existence of a directory |
| -e | Check the existence of a file |
| -r | Check the existence of a file and read permission |
| -w | Check the existence of a file and write permission |
| -x | Check the existence of a file and execute permission |
| -z | string is null, that is, has zero length |
| -n | string is not null. |
Running your script prompts interpreter error
Open your script with vi and execute the following
:set fileformat=unix
Running your script requires more rights
Make your script executable with the following command
chmod +x [scriptname].sh