Continue script if only one instance is running?
73857
Quick-and-dirty way to ensure only one instance of a shell script is running at a time
3693
How to make a package manager wait if another instance of APT is running?
137660
Avoid running the script if a variable is not defined
118250
Launch app only if not already open
141110
How can I automatically run an AppleScript on shutdown or logout?
4860
How to run scripts on start up?
132627
Equivalent of "continue" in Ruby
108006
Run multiple instance of any windows application
34456
How can a script check if it's being run as root?
12086
How to run a script without closing the terminal?
41059
Check to see if python script is running
112706
How do I run a script in the background and leave it running when I log out?
111993
Run two commands on one argument (without scripting)
62756
Running only one Perl script instance by cron
119927
How to repeat prompt to user in a shell script?
101350
Wait for the first subprocess to finish
152938
How can I run a command if one or more conditions in /execute are satisfied?