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Running processes

ps aux

  all processes (a)
  the user (u)
  processes not associated with a terminal (x)

ps -ef
ps -eF


Tree of processes (processes & threads):

pstree -aclp

Process priority

  • -20 is highest priority
  • 19 is lowest priority
    nice -n -20 <command>
renice <nice-value> <pid>

Memory map for a process

 cat /proc/1234/maps
info proc mappings
pmap -d 1234


  • /proc/<id>/environ environment variables
  • /proc/<id>/cmdline command line args/command used to run the process
  • /proc/<id>/maps memory map
  • /proc/<id>/fd open file descriptors

System and library calls

  • ltrace
  • strace

Access control

  • access - Check permissions for the UID and GID of the process (executable file owner / group)
    • Check is done using the calling process's real UID and GID, rather than the effective IDs as is done when actually attempting an operation (e.g., open(2)) on the file.


killall <name>
kill -9 <pid>
kill <pid>