When to press Q to exit in shell?
Use while read input, but due to we want to avoid repeat the echo -en “Press Q to exit : ” statement twice, so we better off to use while true instead (a do while variant):
When to exit Bash with a non-zero status?
This pair of options tell the bash interpreter to exit whenever a command returns with a non-zero exit code. This does not allow you to print an exit message, though. Note also, each command’s exit status is stored in the shell variable $?, which you can check immediately after running the command. A non-zero status indicates failure:
How to exit if a command failed in Linux?
Using exit directly may be tricky as the script may be sourced from other places (e.g. from terminal). I prefer instead using subshell with set -e (plus errors should go into cerr, not cout) : Not the answer you’re looking for?
Which is the exit code in Unix shell?
Exit Codes Exit codes are a number between 0 and 255, which is returned by any Unix command when it returns control to its parent process. Other numbers can be used, but these are treated modulo 256, so exit -10 is equivalent to exit 246 , and exit 257 is equivalent to exit 1 .
Is it possible to put a case statement in a while loop?
However, I was wondering if it’s possible to put a case statement into a while loop? so that when someone chooses the number they can choose another one after that again and again. so the program stops only when the user types in “exit”, for example. Is it possible? or is there a better option than using the while loop?
What do the exit codes mean in grep?
Success is traditionally represented with exit 0; failure is normally indicated with a non-zero exit-code. This value can indicate different reasons for failure. For example, GNU grep returns 0 on success, 1 if no matches were found, and 2 for other errors (syntax errors, non-existent input files, etc).