127 Return code from $?
Value 127 is returned by /bin/sh
when the given command is not found within your PATH
system variable and it is not a built-in shell command. In other words, the system doesn't understand your command, because it doesn't know where to find the binary you're trying to call.
Generally it means:
127 - command not found
but it can also mean that the command is found,
but a library that is required by the command is NOT found.
127 - command not found
example: $caat The error message will
bash:
caat: command not found
now you check using echo $?