Question

I currently have a case statement in bash that looks like so:

restart)
    if kill -0 PID; then
        while kill -0 PID; do
            //exit script
        done
        screen -dmS screen1^M
        screen -S screen1 -p 0 -X stuff '//code here'^M
    else
        //other stuff
    fi
    ;;

When I use this script, the screen meant to be started as screen1 starts as screen1? instead. What is the cause of this, and how would I fix it?

Answer 1

You have extra carriage returns (those funny ^Ms) at the ends of some of your lines. Windows uses a carriage return followed by a linefeed (CRLF) as its line endings, but Linux uses just a plain linefeed, so any extraneous carriage returns are sometimes interpreted as regular characters, particularly in your case.

To fix this, either delete the carriage returns from your script manually, or use a program such as dos2unix(1) to convert the line endings (many other programs can also do this).