proc_pid_comm(5)

💖 proc_pid_comm(5) — the manual page bestie 💖

okay so this one's from proc_pid_comm(5), aka the File Formats Manual, and it's literally about the tiniest file with the biggest main-character energy: the one that holds a process's command name. sit down, hydrate, let's go 🫶

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✨ NAME ✨

/proc/pid/comm — command name. that's it. that's the whole vibe. 🎀

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🌸 DESCRIPTION 🌸

🦋 /proc/pid/comm (since Linux 2.6.33)

bestie. this file exposes the process's comm value — which is just the fancy way of saying the command name associated with the process. it's giving "hi, this is who i am" energy. ✨

and here's the part that lowkey surprises people: different threads inside the same process can have different comm values. you reach each thread's own copy through /proc/pid/task/tid/comm. not me finding out threads have their own little name tags 😭

so can a thread change its name? periodt, yes. a thread may modify its own comm value, OR the comm value of any other thread in the same thread group (peep the discussion of CLONE_THREAD in clone(2) for the receipts), by writing to /proc/self/task/tid/comm. group project rules but make it naming. 💅

and now the fine print, because it matters: strings longer than TASK_COMM_LEN (16) characters — including the terminating null byte — are silently truncated. silently. no warning, no error, no drama text back. your name just gets cut off mid-sentence. 16 chars is the whole budget, girls, spend it wisely 🙈

heads up bestie: it's TASK_COMM_LEN = 16 and that count includes the terminating null byte, so you have less room than you think.

this file is a superset of the prctl(2) PR_SET_NAME and PR_GET_NAME operations, and it's the file that pthread_setname_np(3) uses when you're renaming threads that aren't the caller. so if you've ever wondered how thread renaming actually lands on disk — it's here. 🧚

oh and one more glow-up: the value in this file is the one used for the %e specifier in /proc/sys/kernel/core_pattern. see core(5). so yes, your core file names are riding on this. iconic. 👑

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🎀 SEE ALSO 🎀

• proc(5)

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and that's the whole page, fr fr — short, sweet, and absolutely ate. 💖

this page came to you courtesy of Linux man-pages 6.20, dated 2026-02-08. love that for us. 🦋💜