How to get HOME directory of different user in bash script

Question

I need to execute part of a bash script as a different user  and inside that user s  HOME directory  However  I m not sure how to determine this variable  Switching to that user and calling  HOME does not provide the correct location     running script as root  but switching to a different user    su -  different user echo  HOME   returns  root  but should be  home myuser   Update   It appears that the issue is with the way that I am trying to switch users in my script    different user deploy    create user useradd -m -s  bin bash  different user  echo  Current user   whoami     Current user  root  echo  Switching user to  different user    Switching user to deploy  su -  different user echo  Current user   whoami     Current user  root echo  Current user   id     Current user  uid 0 root  gid 0 root  groups 0 root   sudo su  different user   Current user  root   Current user  uid 0 root  gid 0 root  groups 0 root    What is the correct way to switch users and execute commands as a different user in a bash script

User · Answer

This works in Linux  Not sure how it behaves in other  nixes      getent passwd    OTHER USER   cut -d   -f 6

User · Answer

Quick and dirty  and store it in a variable   USER somebody USER HOME    echo -n   bash -c  cd    USER   amp  amp  pwd

User · Answer

For the sake of an alternative answer for those searching for a lightweight way to just find a user s home dir     Rather than messing with su hacks  or bothering with the overhead of launching another bash shell just to find the  HOME environment variable     Lightweight Simple Homedir Query via Bash  There is a command specifically for this  getent  getent passwd someuser   cut -f6 -d   getent can do a lot more    just see the man page   The passwd nsswitch database will return the user s entry in  etc passwd format   Just split it on the colon   to parse out the fields   It should be installed on most Linux systems  or any system that uses GNU Lib C  RHEL  glibc-common  Deb  libc-bin

User · Answer

So you want to    execute part of a bash script as a different user change to that user s  HOME directory   Inspired by this answer  here s the adapted version of your script      usr bin env bash  different user deploy  useradd -m -s  bin bash   different user   echo  Current user    whoami   echo  Current directory    pwd   echo  echo  Switching user to  different user  sudo -u   different user  -i  bin bash -  lt  lt - EOF      echo  Current user    id       echo  Current directory    pwd   EOF echo  echo  Switched back to   whoami    different user home    eval echo    different user    echo   different user home directory   different user home      When you run it  you should get the following   Current user  root Current directory   root  Switching user to deploy Current user  uid 1003 deploy  gid 1003 deploy  groups 1003 deploy  Current directory   home deploy  Switched back to root deploy home directory   home deploy

User · Answer

Update  Based on this question s title  people seem to come here just looking for a way to find a different user s home directory  without the need to impersonate that user  In that case  the simplest solution is to use tilde expansion with the username of interest  combined with eval  which is needed  because the username must be given as an unquoted literal in order for tilde expansion to work   eval echo  quot   different user quot       prints  different user s home dir   Note  The usual caveats regarding the use of eval apply  in this case  the assumption is that you control the value of  different user and know it to be a mere username  By contrast  the remainder of this answer deals with impersonating a user and performing operations in that user s home directory   Note   Administrators by default and other users if authorized via the sudoers file can impersonate other users via sudo  The following is based on the default configuration of sudo - changing its configuration can make it behave differently - see man sudoers   The basic form of executing a command as another user is  sudo -H -u someUser someExe  arg1          Example  sudo -H -u root env    print the root user s environment  Note   If you neglect to specify -H  the impersonating process  the process invoked in the context of the specified user  will report the original user s home directory in  HOME  The impersonating process will have the same working directory as the invoking process  The impersonating process performs no shell expansions on string literals passed as arguments  since no shell is involved in the impersonating process  unless someExe happens to be a shell  - expansions by the invoking shell - prior to passing to the impersonating process - can obviously still occur   Optionally  you can have an impersonating process run as or via a n impersonating  shell  by prefixing someExe either with -i or -s - not specifying someExe     creates an interactive shell   -i creates a login shell for someUser  which implies the following   someUser s user-specific shell profile  if defined  is loaded   HOME points to someUser s home directory  so there s no need for -H  though you may still specify it  The working directory for the impersonating shell is the someUser s home directory    -s creates a non-login shell   no shell profile is loaded  though initialization files for interactive nonlogin shells are  e g      bashrc  Unless you also specify -H  the impersonating process will report the original user s home directory in  HOME  The impersonating shell will have the same working directory as the invoking process     Using a shell means that string arguments passed on the command line MAY be subject to shell expansions - see platform-specific differences below - by the impersonating shell  possibly after initial expansion by the invoking shell   compare the following two commands  which use single quotes to prevent premature expansion by the invoking shell       Run root s shell profile  change to root s home dir  sudo -u root -i eval  echo  SHELL -  USER -  HOME -  PWD      Don t run root s shell profile  use current working dir      Note the required -H to define  HOME as root s home dir  sudo -u root -H -s eval  echo  SHELL -  USER -  HOME -  PWD   What shell is invoked is determined by  quot the SHELL environment variable if it is set or the shell as specified in passwd 5  quot   according to man sudo   Note that with -s it is the invoking user s environment that matters  whereas with -i it is the impersonated user s  Note that there are platform differences regarding shell-related behavior  with -i or -s    sudo on Linux apparently only accepts an executable or builtin name as the first argument following -s -i  whereas OSX allows passing an entire shell command line  e g   OSX accepts sudo -u root -s  echo  SHELL -  USER -  HOME -  PWD  directly  no need for eval   whereas Linux doesn t  as of sudo 1 8 95p    Older versions of sudo on Linux do NOT apply shell expansions to arguments passed to a shell  for instance  with sudo 1 8 3p1  e g   Ubuntu 12 04   sudo -u root -H -s echo   HOME  simply echoes the string literal  quot  HOME quot  instead of expanding the variable reference in the context of the root user  As of at least sudo 1 8 9p5  e g   Ubuntu 14 04  this has been fixed  Therefore  to ensure expansion on Linux even with older sudo versions  pass the the entire command as a single argument to eval  e g   sudo -u root -H -s eval  echo  HOME    Although not necessary on OSX  this will work there  too    The root user s  SHELL variable contains  bin sh on OSX 10 9  whereas it is  bin bash on Ubuntu 12 04    Whether the impersonating process involves a shell or not  its environment will have the following variables set  reflecting the invoking user and command  SUDO COMMAND  SUDO USER  SUDO UID   SUDO GID  See man sudo and man sudoers for many more subtleties  Tip of the hat to   DavidW and  Andrew for inspiration

User · Answer

I was struggling with this question because I was looking for a way to do this in a bash script for OS X  hence  etc passwd was out of the question  and my script was meant to be executed as root  therefore making the solutions invoking eval or bash -c dangerous as they allowed code injection into the variable specifying the username    Here is what I found  It s simple and doesn t put a variable inside a subshell  However it does require the script to be ran by root as it sudos into the specified user account   Presuming that  SOMEUSER contains a valid username   echo    sudo -H -u   SOMEUSER  -s --  cd    amp  amp  pwd      I hope this helps somebody

User · Answer

The title of this question is How to get  HOME directory of different user in bash script  and that is what people are coming here from Google to find out  There is a safe way to do this  on Linux BSD macOS OSX without sudo or root user pi user home   bash -c  quot cd    printf  q  USER   amp  amp  pwd quot    NOTE  The reason this is safe is because bash  even versions prior to 4 4  has its own printf function that includes    q   quote the argument in a way that can be reused as shell input  See  help printf Compare the how other answers here respond to code injection    quot ls   quot  is not dangerous so you can try this on your machine   But  it could just as easily be  quot sudo rm -rf    quot    user  quot root  ls   quot    printf  quot  q quot   quot  user quot  root    ls       This is what you get when you are PROTECTED from code injection   user home   bash -c  quot cd    printf  quot  q quot   quot  user quot    amp  amp  pwd quot    echo  user home bash  line 0  cd   root  ls    No such file or directory    This is what you get when you ARE NOT PROTECTED from code injection   user home   bash -c  quot cd   user  amp  amp  pwd quot    echo  user home bin boot dev etc home lib lib64 media mnt ono opt proc root run sbin srv sys tmp usr var  root    user home   eval  quot echo   user quot    echo  user home  root bin boot dev etc home lib lib64 media mnt ono opt proc root run sbin srv sys tmp usr var  on Linux BSD macOS OSX as root If you are doing this because you are running something as root then you can use the power of sudo  user pi user home   sudo -u  user sh -c  echo  HOME    on Linux BSD  but not modern macOS OSX  without sudo or root If not  the you can get it from  etc passwd  There are already lots of examples of using eval and getent  so I ll give another option  user pi user home   awk -v u  quot  user quot  -v FS       1  u  print  6    etc passwd   I would really only use that one if I had a bash script with lots of other awk oneliners and no uses of cut  While many people like to  quot code golf quot  to use the fewest characters to accomplish a task  I favor  quot tool golf quot  because using fewer tools gives your script a smaller  quot compatibility footprint quot   Also  it s less man pages for your coworker or future-self to have to read to make sense of it

User · Answer

You want the -u option for sudo in this case  From the man page   The -u  user  option causes sudo to run the specified command as a user other than root    If you don t need to actually run it as them  you could move to their home directory with   lt user gt   As in  to move into my home directory you would use cd  chooban

User · Answer

The output of getent passwd username can be parsed with a Bash regular expression  OTHER HOME                  getent       passwd          OTHER USER                    5                 amp  amp  echo    BASH REMATCH 2

User · Answer

In BASH  you can find a user s  HOME directory by prefixing the user s login ID with a tilde character  For example     echo  bob   This will echo out user bob s  HOME directory   However  you say you want to be able to execute a script as a particular user  To do that  you need to setup sudo  This command allows you to execute particular commands as either a particular user  For example  to execute foo as user bob     sudo -i -ubob -sfoo   This will start up a new shell  and the -i will simulate a login with the user s default environment and shell  which means the foo command will execute from the bob s HOME  directory    Sudo is a bit complex to setup  and you need to be a superuser just to be able to see the shudders file  usually  etc sudoers   However  this file usually  has several examples you can use   In this file  you can specify the commands you specify who can run a command  as which user  and whether or not that user has to enter their password before executing that command  This is normally the default  because it proves that this is the user and not someone who came by while the user was getting a Coke   However  when you run a shell script  you usually want to disable this feature

User · Answer

If the user doesn t exist  getent will return an error   Here s a small shell function that doesn t ignore the exit code of getent   get home       local result  result    getent passwd   1       return   echo  result   cut -d   -f 6     Here s a usage example   da home    get home missing user          echo  User does NOT exist    exit 1      Now do something with  da home echo  Home directory is    da home

User · Answer

I was also looking for this  but didn t want to impersonate a user to simply acquire a path   user path   grep  username  etc passwd cut -f6 -d       Now in your script  you can refer to  user path in most cases would be  home username  Assumes  You have previously set  username with the value of the intended users username  Source  http   www unix com shell-programming-and-scripting 171782-cut-fields-etc-passwd-file-into-variables html

[bash] How to get $HOME directory of different user in bash script?

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