pid(3tcl)

💖 pid — bestie, who even ARE you (process edition) 💖

okay so this is a page from the Tcl Built-In Commands manual, and it's called pid. Yes, like process identifier. Yes, it's short. Yes, it's iconic. Let's go ✨

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🌸 NAME 🌸

pid — Retrieve process identifiers 🫶

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✨ SYNOPSIS ✨

pid ?fileId?

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💅 DESCRIPTION 💅

okay so here's the tea, bestie 🍓

If you hand over the fileId argument, then — and this is the important part — it should normally refer to a process pipeline that got created with the open command. In that case, pid is gonna return a list whose elements are the process identifiers of all the processes in the pipeline, in order. Like, in ORDER order. The way it lines them up?? obsessed. 👑

And lowkey, if fileId refers to an open file that is not a process pipeline, the list will just be empty. No drama, just vibes. 💀

But if you don't give a fileId argument at all? Then pid returns the process identifier of the current process. That's you. That's your main character energy right there. 🌟

Oh and — all process identifiers are returned as decimal strings. Not numbers, not vibes, decimal strings. Periodt. 💅

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🎀 EXAMPLE 🎀

So here's how you print process information about the processes in a pipeline using the SysV ps program, before you read the output of that pipeline. Chef's kiss setup fr fr 😭

set pipeline [open "| zcat somefile.gz | grep foobar | sort -u"]
# Print process information
exec ps -fp [pid $pipeline] >@stdout
# Print a separator and then the output of the pipeline
puts [string repeat - 70]
puts [read $pipeline]
close $pipeline

like?? the way that pipeline just works?? 🦋

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👑 SEE ALSO 👑

• exec(3tcl)
• open(3tcl)

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🌈 KEYWORDS 🌈

file, pipeline, process identifier

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no cap, that's the whole page bestie. short, sweet, and literally does exactly what it says on the tin. iykyk 💜

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and that's a wrap on this lil page from the Tcl manual, version 7.0, dated 7.0 (yes that's what the footer says, don't come for me 🙈). bye bestie, go check on your processes 💖✨