====== Unix ======


===== Shell =====

[[https://stackoverflow.com/questions/8473121/execute-command-without-keeping-it-in-history|Execute command  without keeping it in hostory]]:

  * Sometimes shell commands must be kept form history, e.g. when setting secrets to environment variables for configuring applications according to the [[https://12factor.net/config|Twelve-Factor-App]].
  * Configure the shell to not record history when starting with a space: ''$ export HISTCONTROL=ignorespace''
  * Execute the command with a secret with a leading space: ''$ ⌴export⌴MY_PASSWORD=the-secret''
  * Verified in Bash. The command will not be recorded in ''~/.bash_history''.


===== Permissions =====


==== Users ====

  * Set owner: ''$ chown myfolder myuser''
  * Set owner and group: ''$ chown myowner:mygroup myfolder''
  * Change password: ''$ passwd''
  * List user's groups: ''$ groups somebody''


==== Groups ====

  * Set group: ''$ chgrp mygroup myfolder''
  * Set owner and group: ''$ chown myowner:mygroup myfolder''
  * List group members: ''$ getent group some-group''


==== ACL====

  * Flag s: created folders and files inherit the group of the upper folder. ''$ chmod g+s file.txt''
  * List permissions:
    * ''$ getfacl file.txt''
    * ''$ ls -lV''
  * Set specific group permissions:
    * ''$ setfacl -m u:somebody:rwx file.txt''
    * ''$ setfacl -m g:some-group:rw file.txt''
  * Set default group permissions:
    * ''$ setfacl -m default:g::rwx file.txt''
    * ''$ setfacl -m default:g:some-group:r file.txt''
  * Remove a group: ''$ setfacl -x g:some-group file.txt''
  * http://manpages.ubuntu.com/manpages/xenial/man1/setfacl.1.html