I want to list all services that starts with the letters lc-. Then I want to restart them.
How can I attchive this? I was thinking something like:
systemctl -l | grep ?? | systemctl restart ???
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2 Answers
You can list the unit files with..
systemctl list-unit-files | grep -Eo '^lc-.*\.service'
-E means you are going to use an extended regex expression.
-o means you want only the matching parts.
'^lc-.*\.service' is the regular expression to get only those services that start with 'lc-'.
Then to restart all of them you can use wildcards in your command
systemctl restart 'lc-*'
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@kos OP did ask for 'lc' not 'ls' as far as I can see. '^lc-[^ ]*' will capture lines starting with 'lc-' and omit the extra info after the first word. I've made the other changes you've suggested. Commented Jun 18 at 19:13
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2Note that
restartis not limited to restarting already started/running units but will also start those which aren’t already started/running if they match that pattern.– RaffaCommented Jun 18 at 19:27 -
2(Small nit: you don't really need to use
-Eas you're not using any extended regex feature)– kosCommented Jun 18 at 19:30 -
3... there's
try-restartwhich according to the man page only restarts already-running units Commented Jun 18 at 20:09 -
1Using @steeldriver 's last suggestion along with a pattern such as
lc-*.service, to restrict the targets to only services as asked in the question, is the best way to tackle this and makes jumping through hoops the way I did in my answer unnecessary:systemctl try-restart 'lc-*.service'– kosCommented Jun 19 at 5:43
systemctl can filter by unit type and unit state on its own, not to mention it can print the output as a JSON file, which allows extremely robust parsing, so you could print only running services as a JSON file:
systemctl --type=service --state=running --output=json
filtering out elements whose unit key's value doesn't start with lc-, printing just the unit's name:
jq -r '.[] | .unit | select(test("^lc-"))'
passing the output to xargs -r + sudo systemctl restart (the -r switch will prevent xargs from running sudo systemctl restart in case no running service matching the criteria was found; note that valid unit names can't include whitespace per systemd's specifications so piping the output to xargs -r directly is safe):
xargs -r sudo systemctl restart
Putting everything toghether:
systemctl --type=service --state=running --output=json |
jq -r '.[] | .unit | select(test("^lc-"))' |
xargs -r sudo systemctl restart
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sudo systemctl --type=service --state=running --output=json | sudo jq -r '.[] | sudo .unit | sudo select(test("^ls-"))' | sudo xargs systemctl restart jq: error: syntax error, unexpected IDENT, expecting end of file (Unix shell quoting issues?) at <top-level>, line 1: .[] | sudo .unit | sudo select(test("^ls-")) jq: 1 compile error Too few arguments.– EuropaCommented Jun 18 at 9:20
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@Europa You're adding way too many
sudoand some of them are breaking parsing, just add asudobefore thesystemctlcommand:systemctl --type=service --state=running --output=json | jq -r '.[] | .unit | select(test("^ls-"))' | xargs sudo systemctl restart– kosCommented Jun 18 at 9:23 -
1@Europa "
Too few arguments" is because there were no results for the expression"^ls-"... You needed"^lc-"instead.– RaffaCommented Jun 18 at 9:37 -
@Raffa Thanks for implicitly pointing out the possible issue, luckily nothing would break if no service matches the regex in this case, but to be honest it's incidental, I didn't explicitly cater for that :) however they're also putting
sudoinside thejqexpression, so maybe there are services starting withlc-and thejqexpression, broken as is, is breaking the pipe. On that note I have yet to figure out if they want to matchlc-orls-, they wrote two different things in the title and in the body of the question...– kosCommented Jun 18 at 9:45 -
You're welcome, that's a minor issue which is not your fault ... However, your solution is as accurate, controlled, and efficient as it gets IMHO– RaffaCommented Jun 18 at 9:56