What is the Difference between ConditionPathExists= and ConditionPathExists=| in systemd?
I need check a file not exist before i start my service in Systemd. I see two case in [Unit]:
ConditionPathExists=!/tmp/abc
and
ConditionPathExists=|!/tmp/abc
are they the same? Can anybody help me explain if they are different?
Answer
Sometime you specify multiple files like:
ConditionPathExists=!/tmp/abc
ConditionPathExists=!/tmp/abe
Now if any of the condition isn't satisfied, it doesn't start service. It's like and operations.
Now if you use:
ConditionPathExists=|!/tmp/abc
ConditionPathExists=|!/tmp/abe
If any of these conditions is satisfied, it will run the service.
Condition checks can be prefixed with a pipe symbol (|) in which case a condition becomes a triggering condition. If at least one triggering condition is defined for a unit, then the unit will be executed if at least one of the triggering conditions apply and all of the non-triggering conditions
It's like OR operations