Linux – Change EUID of running process

Have a look at reptyr, which does exactly that. The github page has all the information.

reptyr - A tool for "re-ptying" programs.

reptyr is a utility for taking an existing running program and attaching it to a new terminal. Started a long-running process over ssh, but have to leave and don't want to interrupt it? Just start a screen, use reptyr to grab it, and then kill the ssh session and head on home.

USAGE

reptyr PID

"reptyr PID" will grab the process with id PID and attach it to your current terminal.

After attaching, the process will take input from and write output to the new terminal, including ^C and ^Z. (Unfortunately, if you background it, you will still have to run "bg" or "fg" in the old terminal. This is likely impossible to fix in a reasonable way without patching your shell.)

cat /proc/<pid>/environ

If you want to have pid(s) of a given running executable you can, among a number of other possibilities, use pidof:

AlberT$ pidof sshd   
30690 6512 

EDIT:

I totally quote Dennis Williamson and Teddy comments to achieve a more readable output. My solution is the following:

tr '\0' '\n' < /proc/<pid>/environ