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28 lines
1.2 KiB
Markdown
28 lines
1.2 KiB
Markdown
# List PID And Name Of Current Shell Process
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In Julia Evans' [How to add a directory to your
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PATH](https://jvns.ca/blog/2025/02/13/how-to-add-a-directory-to-your-path/),
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she shows off an odd-looking command for determining what shell (e.g. bash or
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zsh) you are currently running.
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```bash
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$ ps -p $$ -o pid=,comm=
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38105 -zsh
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```
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I already know I'm running `zsh`, but I thought this command was interesting
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enough to dig into and break down.
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- The `ps` command lists processes that "have controlling terminals"
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- The `$$` is a special shell variable representing the PID of the current process (try `echo $$`)
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- The `-p` flag allows you to specify a PID for `ps` to grab, in this case, the `$$` PID
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- The `-o` flag allows us to specify the output format, such as the PID and command name
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- The `=` after `pid` and `comm` tell `ps` to exclude headers from the output
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Additionally, I noticed that it output `-zsh` (not just `zsh`). That leading
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hyphen seems to indicate that [this `zsh` process is a _login
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shell_](https://unix.stackexchange.com/a/46856/5916). That means it was the
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process used to initiate an interactive shell session and something like the
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`.zprofile` would have been sourced as part of that.
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