Useful project, I love all things terminal, so I also enjoyed your project.
You enjoyed the project because you love the terminal?
Show HN: Linux CLI tool to provide mutex locks for long running bash ops
11–20 of 22 posts
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#12Why not https://man7.org/linux/man-pages/man2/flock.2.html ?
Because that's a syscall ;) https://man7.org/linux/man-pages/man1/flock.1.html is the command line manual. I would say one good reason is that waitlock myapp & JOB_PID=$! # ... do exclusive work ... kill $JOB_PID is a lot easier to use and remember than (; flock -n 9 || exit 1; # ... commands executed under lock ...; ) 9>/var/lock/mylockfile
Flock can be used in a single line for example for cronjobs.
Flock -s file && script.
Pretty simple. (I forgot the argument, I think is -s..
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#13Earlier quoted context omitted.
Because that's a syscall ;) https://man7.org/linux/man-pages/man1/flock.1.html is the command line manual. I would say one good reason is that waitlock myapp & JOB_PID=$! # ... do exclusive work ... kill $JOB_PID is a lot easier to use and remember than (; flock -n 9 || exit 1; # ... commands executed under lock ...; ) 9>/var/lock/mylockfile
Why (; flock -n 9 and not ( flock -n 9 ?
It's a "for" loop.
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#14Why not https://man7.org/linux/man-pages/man2/flock.2.html ?
flock is indeed built-in: `flock -xn /tmp/mylock.lock -c "echo running locked command"` does mutex locking in bash. Your tool might offer better ergonomics or features beyond flock's capabilities?
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#15We already have lockfile: https://manpages.debian.org/stable/procmail/lockfile.1.en.ht...>.
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#16I don’t know the exact threshold at which you should use a real programming language instead of a bash script. But this type of work definitely exceeds it.
Sometimes you have a cron job that takes longer than it should (but inconsistently so), and another cron job that clobbers what that cron job is doing.
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#17Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#18Earlier quoted context omitted.
It's a "for" loop.
Could you elaborate?
A for loop in a shell script may sometimes look like this:
`for ((i = 0 ; i Here this is essentially a "while" loop, meaning it will keep executing the commands as long as we don't reach `exit 1`.
(; flock -n 9 || exit 1; # ... commands executed under lock ...; )
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#19Why not https://man7.org/linux/man-pages/man2/flock.2.html ?
Because that's a syscall ;) https://man7.org/linux/man-pages/man1/flock.1.html is the command line manual. I would say one good reason is that waitlock myapp & JOB_PID=$! # ... do exclusive work ... kill $JOB_PID is a lot easier to use and remember than (; flock -n 9 || exit 1; # ... commands executed under lock ...; ) 9>/var/lock/mylockfile
just pushed a change so now it's:
waitlock myapp & #... do stuff waitlock --done myapp
Re: Show HN: Linux CLI tool to provide mutex locks for long running bash ops
#20Useful project, I love all things terminal, so I also enjoyed your project.
You enjoyed the project because you love the terminal?
Good enough for me. I created the project because I love terminal, and wanted to make something using Claude (to learn how this tool works, strictly for personal enrichment) that solves a small problem I had with some overlapping cron job management.