How to Get Basic Information About a Process in Linux

May 16, 2020

There is a way to get information about any process (with according permissions) using filesystem operations only. You need no additional tools besides what you already have on your system. In most cases cat will be enough.

Actually, for this post, we will familiarise with such files that can be displayed with cat and we will begin with the real simple ones

/proc/<pid>/cmdline

It will produce an output with a full command line with the process being run.

$ cat /proc/33439/cmdline
/bin/sh/usr/bin/fakeroot--bash-hB/usr/bin/makepkg-F-cf--noconfirm--noextract--noprepare--holdver%

/proc/<pid>/comm

That file contains a command name that was runned

$ cat /proc/33439/comm
fakeroot

/proc/environ

Will output all environment variables for the process

$ cat /proc/30306/environ
ALACRITTY_LOG=/tmp/Alacritty-30279.logBINARYEN=/usrBINARYEN_ROOT=/usrCOLORTERM=truecolorDBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/busDISPLAY=:0.0GTK_MODULES=canberra-gtk-moduleHG=/usr/bin/hg