Exit codes in bash indicate the previous command’s termination status. 0 indicates that command completion was successful while 1 indicates that command execution failed.
We can check the exit code generated by last command by using $?
$ echo $?
It’s not only 1 that indicates unsuccessful completion, anything greater than 1 is a sign of command failure. Standard error code are listed here:
| Exit Code | Description |
|---|---|
| 0 | Successful execution |
| 1 | Unsuccessful execution catchall |
| 2 | Incorrect use of shell builtin |
| 126 | Command can not execute |
| 127 | Command not Found |
| 128 | Incorrect exit code argument |
| 128 + num | Fatal error signal “num” |
| 130 | Script killed with CTRL + C |
| 255+ | Exit code is out of range |
Note: Exit code is an integer value between 0 and/or 255.