How do I use su to execute the rest of the bash script as that user

Question

I ve written a script that takes  as an argument  a string that is a concatenation of a username and a project  The script is supposed to switch  su  to the username  cd to a specific directory based upon the project string   I basically want to do   su  USERNAME    cd  home  USERNAME  PROJECT    svn update      The problem is that once I do an su    it just waits there  Which makes sense since the flow of execution has passed to switching to the user  Once I exit  then the rest of the things execute but it doesn t work as desired   I prepended su to the svn command but the command failed  i e  it didn t update svn in the directory desired    How do I write a script that allows the user to switch user and invoke svn  among other things

User · Answer

Much simpler  use sudo to run a shell and use a heredoc to feed it commands      usr bin env bash whoami sudo -i -u someuser bash  lt  lt  EOF echo  In  whoami EOF echo  Out  whoami    answer originally on SuperUser

User · Answer

Inspired by the idea from  MarSoft but I changed the lines like the following   USERNAME  desireduser  COMMAND  0 COMMANDARGS    printf    q           if     whoami       USERNAME     then   exec sudo -E su  USERNAME -c   usr bin bash -l  COMMAND  COMMANDARGS    exit fi   I have used sudo to allow a password less execution of the script  If you want to enter a password for the user  remove the sudo  If you do not need the environment variables  remove -E from sudo   The  usr bin bash -l ensures  that the profile d scripts are executed for an initialized environment

User · Answer

Use sudo instead  EDIT  As Douglas pointed out  you can not use cd in sudo since it is not an external command  You have to run the commands in a subshell to make the cd work   sudo -u  USERNAME -H sh -c  cd    PROJECT  svn update      sudo -u  USERNAME -H cd    PROJECT sudo -u  USERNAME svn update     You may be asked to input that user s password  but only once

User · Answer

This worked for me  I split out my  provisioning  from my  startup       Configure everything else ready to run    config vm provision  shell  path   provision sh    config vm provision  shell  path   start env sh   run   always    then in my start env sh     usr bin env bash  echo  Starting Server Env   java -jar  usr lib node modules selenium-server-standalone-jar jar selenium-server-standalone-2 40 0 jar   amp    cd  vagrant projects myproj  amp  amp  sudo -u vagrant -H sh -c  nohup npm install 0 lt  amp -  amp  gt  dev null  amp  bower install 0 lt  amp -  amp  gt  dev null  amp    cd  vagrant projects myproj nohup grunt connect server keepalive 0 lt  amp -  amp  gt  dev null  amp  nohup apimocker -c  vagrant projects myproj mock api data config json 0 lt  amp -  amp  gt  dev null  amp

User · Answer

You need to execute all the different-user commands as their own script  If it s just one  or a few commands  then inline should work  If it s lots of commands then it s probably best to move them to their own file   su -c  cd  home  USERNAME  PROJECT   svn update  -m   USERNAME

User · Answer

It s not possible to change user within a shell script   Workarounds using sudo described in other answers are probably your best bet     If you re mad enough to run perl scripts as root  you can do this with the   lt       gt      variables which hold real effective uid gid  e g       usr bin perl -w  user   shift  if     lt           gt    getpwnam  user           getgrnam  user    else       die  must be root to change uid     system  whoami

User · Answer

The trick is to use  sudo  command instead of  su   You may need to add this   username1 ALL  username2  NOPASSWD   path to svn   to your  etc sudoers file  and change your script to   sudo -u username2 -H sh -c  cd  home  USERNAME  PROJECT  svn update     Where username2 is the user you want to run the SVN command as and username1 is the user running the script   If you need multiple users to run this script  use a  groupname instead of the username1

User · Answer

Use a script like the following to execute the rest or part of the script under another user      bin sh  id  exec sudo -u transmission  bin sh -  lt  lt  eof  id  eof

User · Answer

Here is yet another approach  which was more convenient in my case  I just wanted to drop root privileges and do the rest of my script from restricted user   you can make the script restart itself from correct user  Let s suppose it is run as root initially  Then it will look like this      bin bash if    UID -eq 0    then   user  1   dir  2   shift 2       if you need some other parameters   cd   dir    exec su   user    0  --          nothing will be executed beyond that line      because exec replaces running process with the new one fi  echo  This will be run from user  UID

[bash] How do I use su to execute the rest of the bash script as that user?

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