reredirect(1)

📦 version 2026-02, in nixos 26.05, nixpkgs unstable

💅 reredirect(1) — like, the redirect-your-running-process girly ✨

okay so real talk, this is a page from the General Commands Manual, and it's about the icon that is reredirect. buckle up bestie 🎀

✨ NAME ✨

reredirect — the tool that dynamically redirects the outputs of a process that's already running 👑 no restart, no relaunch, we just slide in 💅

🦋 SYNOPSIS 🦋

reredirect [-i FILE |-i FD ] [-m FILE |-o FILE |-e FILE |-I FD |-O FD
|-E FD ] [-N] [-d] PID

🌸 DESCRIPTION 🌸

okay so reredirect is this utility that takes a program that is already running and attaches its input/outputs — that's standard output and error output, iykyk — to files or to another process. literally just vibes-based plumbing 🫶

the simple usage is giving:

reredirect -m FILE PID

and it will redirect the outputs of PID to FILE. slay ✨

you can also redirect standard input, output and error output into different files, which is honestly so main character:

reredirect -i FILE1 -o FILE2 -e FILE3 PID

and just so you know, the -m option is literally just a shortcut to -o FILE -e FILE. that's it. that's the whole thing 💖

after it launches, reredirect gives you a command to restore the state of PID. it will look something like:

reredirect -N -I 4 -O 5 -E 3 5453

and yes — -I, -O and -E act like -i, -o and -e but with file descriptors that are already opened in PID. they're only used to restore the previous state of PID, no cap 🧚

💅 OPTIONS 💅

  • -i FILE — the file you want to redirect stdin to 🍓
  • -o FILE — the file you want to redirect stdout to 💜
  • -e FILE — the file you want to redirect stderr to 🌈
  • -m FILE — same than -o FILE -e FILE, a two-for-one deal 💖
  • -I FD — redirect stdin to this file descriptor. mainly used to restore process input 🔥
  • -O FD — redirect stdout to this file descriptor. mainly used to restore process outputs ⭐
  • -E FD — redirect stderr to this file descriptor. mainly used to restore process outputs 👑
  • -N — do not save the previous stream, we're moving on bestie 🙈
  • -V — print the version of reredirect and exit 💫
  • -h — print a usage message and exit 🎀
  • -v — print verbose debug output while running, for the nosy girlies 🔍

⚠️ NOTES ⚠️

okay this part matters so pay attention bestie 😭

reredirect depends on the ptrace(2) system call to attach itself to the remote program. and on Ubuntu Maverick and higher, that ability is disabled by default for security reasons. yeah. 💀

you can enable it temporarily by doing:

# echo 0 > /proc/sys/kernel/yama/ptrace_scope

as root, or permanently by editing the file /etc/sysctl.d/10-ptrace.conf, which — fun fact — also contains more information about this setting 🦋

🐛 BUGS 🐛

bugs should be reported to the author (see below) or via the issue tracker on GitHub. please be nice about it 🫶

💜 AUTHORS 💜

reredirect was mainly written by Jérôme Pouiller <jezz@sysmic.org>. you can contact hom — yes, the manpage says "hom", we love a typo moment 💅 — for any questions or bug reports.

also, reredirect (and especially all the ptrace layer) is based on the reptyr programm (typo number two, iconic). reptyr was written by Nelson Elhage <nelhage@nelhage.com> ✨

🌟 HOMEPAGE 🌟

⟨https://github.com/jerome-pouiller/reredirect⟩

and that's the whole page, bestie 🎀 this gem dropped 26 Aug 2014 with the source/version stamp reredirect(1) — go redirect something and live your truth, periodt 💖👑

📦 where this page comes from