systemd - Giving my service multiple arguments

Yes you can! Define them in a file somewhere and add them to EnvironmentFile in your systemd Service. For example, say the contents of /etc/.progconf are:

ARG1=-o
ARG2=--verbose

And your .service file:

EnvironmentFile=/etc/.progconf
ExecStart = /usr/bin/prog $ARG1 $ARG2

You can write to that file if you need to change them on the go. A service shouldn't change its options very often, maybe consider autostarting or cron if you need to achieve that.

For more examples check: https://wiki.archlinux.org/index.php/Systemd/Services

I wanted to do the same thing, but without a separate file for each combination of arguments. I found that I could pass one long argument with spaces and then use systemd's environment variable space-splitting feature to separate the arguments.

I made a service with filename [email protected] (note the trailing 'at sign' which is required when a service takes arguments).

[Unit]
Description=Test passing multiple arguments

[Service]
Environment="SCRIPT_ARGS=%I"
ExecStart=/tmp/test.py $SCRIPT_ARGS

I run this with sudo systemctl start argtest@"arg1 arg2 arg3".service and it passes arg1, arg2 and arg3 as separate command-line arguments to test.py.

Easiest I have found is:

ExecStart=/bin/bash -c "\"/path/with spaces/to/app\" arg1 arg2 arg3 \"arg with space\""

Keeps it all self contained.

Having said that, I have found that at least on Ubuntu 18.04 LTS, I don't even need to do that, I can do this and it works fine:

ExecStart="/path/with spaces/to/app" arg1 arg2 arg3 "arg with space"

$vars work as arguments with this pattern as well.