su is a utility to run a shell or other command as another user (root by default).

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2
votes
1answer
45 views

root login silently fails

After some months of not touching it I wanted to login to one of our virtual servers to update OpenSSL, because of the heartbleed thing. The server is running Debian 7, sudo is not installed. I ...
8
votes
2answers
486 views

I Can't login as root with su command, but I can with SSH

How is it possible that I cannot log in as root by su root or su (I get incorrect password error), but I can log in by ssh root@localhost or ssh root@my_local_IP with the same password? I'm using ...
3
votes
1answer
648 views

Command : must be run from a terminal

I have a shared hosting account, I logged using ssh. when I type for example su I had this output : su: must be run from a terminal Is this error relative to the fact that I don't have sufficient ...
8
votes
2answers
113 views

How do I elevate privileges in the middle of pipeline?

My guess was as follows: echo "Generating some text" | su - -c cat >/output/file But su says: su: must be run from a terminal What would you do?
3
votes
2answers
81 views

Passing arguments to su-provided shell

man su says: You can use the -- argument to separate su options from the arguments supplied to the shell. man bash says: -- A -- signals the end of options and disables further option ...
1
vote
1answer
73 views

Why would we su without -? [duplicate]

When we do su John I switch as user John. When we do su - John I switch as user John having user John's environment. As far as I can see the first option is useless. What is the use of switching to ...
2
votes
2answers
76 views

How do I emulate su's behavior with sudo?

I'm trying to make sudo ask for target password, except when run by root. Here's what I do: Defaults:!root targetpw This way it asks for my password, and if I make it like this: Defaults:yuri ...
1
vote
2answers
34 views

How to log out of su and another user

So when I am logged in as a standard user in an ssh session and then su to root, how can I log out of both accounts with a single command? Rather than: root@host:/exit user@host:/exit something ...
1
vote
1answer
15 views

Changing the PATH variable for a process running as a user on Linux

I have a server application which I start using an init.d script and run as a user: su $USER -c "${PLAY} start ${APPLICATION_PATH} --%prod-test >/dev/null" The application needs ffmpeg, which is ...
2
votes
1answer
37 views

Impossible to execute a command by using su for another (system) user

I've created my user like this: sudo adduser --disabled-password --system --home /var/lib/deluge --gecos "Deluge server" --group deluge The content of /etc/passwd: deluge:x:110:114:Deluge ...
2
votes
2answers
209 views

How to source correct startup scripts on interactive, non-login shell

I'm trying to set up a sane/usable environment in a barebones OpenSolaris-derivative (OmniOS, a distribution of Illumos/OpenIndiana). I have all the plumbing code I need in .profile, .inputrc, and ...
23
votes
6answers
12k views

What is the need for 'fakeroot' command in linux

Why do we need fakeroot command at all? Can't we simply use the sudo or su commands? The man page says: fakeroot - run a command in an environment faking root privileges for file manipulation ...
1
vote
1answer
95 views

“su” with error “X11 connection rejected because of wrong authentication.”

As root, I'm connecting to a remote host to execute a command. Only "standarduser" has the appropriate id-file and correct .ssh/config, so I'm switching the user first: su standarduser -c 'ssh -x ...
0
votes
3answers
57 views

Can sudo to user but 'run command as' is denied?

I was wondering how to run a command as another user from a script without password. sudo -l return: (root) NOPASSWD: /bin/su - someuser There is no problem to sudo as someuser. Command sudo su - ...
1
vote
1answer
39 views

super user group or user?

I am using the following command in Oracle Exadata: sudo su - odiadmin As sudo prompts for my own password, I am wondering if I upgrade myself to super user or do I switch to superuser ...
2
votes
3answers
256 views

How to login as root from Bash and do stuff

This is my simple bash: cat test.sh #!/bin/bash echo "hello" su - root -c /path/to/script.sh <<EOF password EOF whoami echo "good bye" But I get this error: ...
1
vote
2answers
75 views

Script to su -c into a screen is not working as intended

I'm working on a script that will allow me to load up a screen from a user via sudo and su -c. However, when I use it, it will just show the shell of the user: sudo su -c "script /dev/null; screen -r ...
2
votes
2answers
292 views

Cannot connect to X server :0.0 as superuser

When I am online, I get following error and the tool does not start: [root@dhcppc9 lin64]# ./ise No protocol specified _pn: cannot connect to X server :0.0 But everything is OK when I am not a ...
0
votes
0answers
45 views

running a command as a less privileged user: `sudo -u` vs `su` being run as root

in an startup-script that is typically being run as user root, i would like to start a program (actually, a server) as a less-privileged user. the script originally used su -s /bin/sh -c ...
1
vote
3answers
137 views

Why is the 'sudo' password different than the 'su root' password

On my personal machine, I often type sudo in front of certain commands in order to accomplish administrative tasks. I had hoped to avoid doing this throughout the day, by typing su root and providing ...
0
votes
1answer
55 views

Why can't I su when if I am in the wheel group in OpenBSD?

Using a OpenBSD 5.4 (GENERIC) #37: Tue Jul 30 15:24:05 MDT 2013 I created a new user named "bela" and added it to the wheel group: # adduser Use option ``-silent'' if you don't want to see all ...
3
votes
1answer
119 views

Running GUI application as another (non-root) user

Let's say I have 2 user accounts user1 and user2. When I login as user1, and then switch to user2 using su, I can execute command-line programs, but GUI programs fail. Example: user1@laptop:~$ su - ...
4
votes
1answer
104 views

Is there any point in using `sudo` when you are the sole user of your machine?

I'd like to know if there is any reason why I should use sudo instead of su, taking into account that I am the owner and sole user of my machine (and hence have root access whenever I want). Also, in ...
1
vote
0answers
213 views

Automate `pbrun su` via plink

I am trying to automate an sFTP process for our project. When I login with PuTTY and manually type the command pbrun su - user1, root access is given to user1 and I am able to do the sFTP process. I ...
0
votes
1answer
89 views

How to get pid of su --session-command file thats ran on there [closed]

This line ran in a script su --session-command="$javaCommandLine & >>$serviceLogFile 2>&1 & echo \$! >$pidFile" $serviceUser || return 1 pid="$(<$pidFile)" echo $pid The ...
4
votes
1answer
626 views

Automate login with sudo and su

I know the security risks, but I am performing this experiment/excercise on an old, seldom used *nix machine I have laying around the house. So doing this excerise will not bring any security risk to ...
2
votes
2answers
911 views

su - user doesn't work for users without a password

I've created a user on CentOS with useradd -M username. Now, I want to become that user just like su - username. It asks me for a password for that user but I didn't set a password for that user. As ...
7
votes
3answers
252 views

Difference between sudo -i and sudo su [duplicate]

I was wondering what the difference is between sudo -i and sudo su?
1
vote
0answers
52 views

can't access account with empty password

I used the passwd command to remove the password for my account. Now, when I try to use su to log in to my account, it won't let me enter an empty password. So now, I can't access my account. Any ...
2
votes
2answers
944 views

How can I mimic `sudo su - user` in a script?

I need to deploy my app to server called lovelyplace by a Fabric script. Unfortunately, the server's setup is horrible, but I can do nothing about it - I have to live with it. There is one non-root ...
4
votes
2answers
212 views

How do I execute a command on login for a system user with no home folder and no personal .bashrc file?

I set these users' home folders through the /etc/passwd file, but when they log in I would like them to activate a python virtualenv. If they had a personal .bashrc file, I'd just include the activate ...
7
votes
4answers
1k views

sudo permission denied but su grants permission

this is the first occurrence where su was required for me. I read an article about changing the value in /sys/devices/virtual/backlight/acpi_video0/brightness to alter my laptop's screen brightness. ...
1
vote
2answers
860 views

How can i run a part of a script as a different user?

#!/bin/ksh (some code) Log=~/my.log chown USER1 filename su - USER1 -c " date | tee -a ${Log} 2>&1; cd /blah/blah if [ SOMECONDITION ] then sh ./somescript.ksh > logfile fi exit" | tee -a ...
1
vote
3answers
247 views

How to gain root privileges for specific user if we have root password? [closed]

Can someone suggest how can I change process privileges in Linux to root ? Assume, I have a normal process running under some user-consider me. Now my script should create some users using 'useradd' ...
1
vote
2answers
125 views

Can't run su after changing permissions to su file

I am running Linux Slackware 14.0. I wanted to allow to do su only to the members of wheel group, so I modified the permissions of /bin/su and /usr/bin/sudo files to this: bash-4.2# ls -la /bin/su ...
5
votes
1answer
112 views

How to allow to run su instantly after I added the user to the appropriate group

I have the su executable with the following permissions: bash-4.2# ls -la /bin/su -rws--s--- 1 root wheel 59930 Sep 14 2012 ./su When I am logged in as a user, not in the wheel group and try to ...
0
votes
3answers
268 views

Create a file as a different user and group

I have a bash script with downloads some files, and then needs to set the owner to apache, and the group to a particular user group (that apache is not a member of). Is there a way to create those ...
2
votes
2answers
290 views

how to ssh -Y and then su - <another user> and still forward X applications to your local machine

it is easy enough to 'fetch' (ie draw locally) a remotely running linux application: If I ssh -Y to the remote machine and run an application, that application will surely enough pop up in my local ...
1
vote
1answer
380 views

How does this su -c “…” command seem to pass two commands instead of one?

I am trying to understand the script below and I am confused about the su line. I understand the postgres command line arguments. when I do man su the manual says -c, --command=COMMAND ...
0
votes
1answer
52 views

I want to create a script so that I don't have to type su and password every time [closed]

I want to create a script so that I don't have to type su and the password for logging into root every time.
5
votes
4answers
774 views

Why can't we execute a list of commands as different user without sudo?

This question has been asked in a different way in other forums. But there has not been a decent explanation why you can't do the below in bash. #!/bin/bash command1 SWITCH_USER_TO rag command2 ...
0
votes
2answers
3k views

Avoid asking password if `su -m user command` is used under `user`?

If I run the script containing su -m user service userservice start under root user, I do not need to enter the password. But when I run it under user user, it asks passwords all the time. That really ...
1
vote
3answers
92 views

Is there any way to disable shutdowning remote machine?

I sometimes mistakenly shutdown the remote machine by using sudo init 0, so I wrote something like in one of my rc files: alias sudo='sudo ' if [ $SSH_CLIENT ]; then alias init 'echo Never use init ...
1
vote
3answers
91 views

Confused on user and su in linux

How could I run a script as a specific user (non-root)? As this? sudo su - john /usr/share/script.pl for user john?
1
vote
2answers
106 views

Staggering the authentication delay on failed `su` or `sudo` [duplicate]

I'm about to start my new job as a sysadmin and I've been thinking about implementing a cooldown feature on su or sudo. The cooldown prevents the user from using these commands for a few seconds after ...
0
votes
0answers
94 views

CentOS custom livecd using su throws: “Error setting value: Failed to contact configuration server…”

I am building my own custom CentOS Live CD with tools and settings I need. But if I want to root myself using "su" I always get this error message: Error setting value: Failed to contact ...
2
votes
2answers
328 views

Setting umask for su root

In my user account I set the umask to be 022 with my .bashrc, but I want root to use a umask of 077 no matter how I become root (e.g., logging in directly as root on a tty or using sudo or su). If I ...
1
vote
1answer
73 views

ssh key authentication not working from network/if-up.d/ scripts

I have two nearly identical scripts in network/if-up that need to access SSH keys. Permissions on SSH private keys are 600, so how can my scripts access these keys? I would prefer to keep the SSH ...
2
votes
3answers
918 views

su: Permission denied despite correct password

In my new Gentoo installation, su doesn't work as my non-root user: After entering the correct password I get the message "su: Permission denied". What could be causing this? I have already tried ...
10
votes
4answers
7k views

Why doesn't “sudo su” in a shell script run the rest of the script as root?

A sample script can be as below: #!/bin/bash sudo su ls /root When using ./test.sh as the normal user, instead run ls as super user and exit, it switches to root; and when I logout, it executes ls ...