While installing QT, I met this command:
sudo -s chmod u+x QtSdk-offline-linux-x86_64-v1.2.1.run
I wonder what -s means here.And it seems similar here:
sudo -s ./QtSdk-offline-linux-x86_64-v1.2.1.run -style cleanlooks
sudo -s runs a shell with root privileges
"The -s (shell) option runs the shell specified by the SHELL
environment variable if it is set or the shell as specified in
passwd(5). If a command is specified, it is passed to the shell for
execution. Otherwise, an interactive shell is executed."
From here.
As mentioned in the comments above, check out the man info:
Type man sudo to your command line.
Find -s in the list of commands for a good explanation.
Related
Both sudo -s and sudo su makes user root. is there any some difference?
With sudo -s
with sudo su
From man sudo:
-s, --shell
Run the shell specified by the SHELL environment variable if it is set or the shell specified by the invoking user's password
database entry. If a command is specified, it is passed to the shell for execution via the shell's -c option. If no command is
specified, an interactive shell is executed.
So -s keeps your current shell (bash in this case), while omitting it uses the shell of the root user (sh). Myself, I prefer sudo -Es to keep both my shell and environment variables.
I am trying to execute screen as another user using sudo.
I'm using the command:
echo 'userpassword' | /usr/bin/sudo -u 'myuser' -S '/usr/bin/screen -ls'
Any help found on the internet says that the sudo clears the environment variables (like PATH). So I decided to use the full path to the applications but I'm still getting the command not found error.
Error:
sudo: /usr/bin/screen -ls: command not found
Sudo is installed on the system.
Screen is installed on the system.
For sudo, I have tried the -E and -H flag but it doesn't help.
I tried to set PATH variable using something like this:
... | /usr/bin/sudo -u 'myuser' -S 'env PATH=$PATH; /usr/bin/screen -ls'
Supposedly the $PATH was suppose to expand before the command executes but I was getting other errors...
Can someone provide a command that will let me execute commands as another user and explain what each part of the command does so I can understand it?
Thanks.
Try,
export PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:$PATH
Probably you replaced the path variable while trying to set a new path variable.
Going forward, do 'echo $PATH' before adding a new path variable.
There doesn's seem to be any need to encapsulate command in quotes, without them it even works.
echo 'userpassword' | /usr/bin/sudo -u 'myuser' -S screen -ls
This question already has answers here:
How to fix 'sudo: no tty present and no askpass program specified' error?
(30 answers)
Closed 6 years ago.
I have a shell script which creates a user and executes another script as that user
sudo useradd -m devops
sudo passwd devops
sudo adduser devops sudo
su - devops -c "sh /path/to/myscript.sh"
This script creates the user,sets the password and adds user to sudo group as expected.
myscript.sh contains commands which uses sudo previlages. (sudo apt-get update, sudo apt-get install software-properties-common etc.). And other commands like ssh-keygen,curl and wget.
All commands except the one's with sudo are executed correctly and producing results as excepted.
But commands having sudo fails by giving the error "no tty present and no askpass program specified"
Why does this happen in this case and how can I overcome this?
I have seen similiar questions but will be thankful if I get a clear explanation in this context,thank you.
Try to replace this:
su - devops -c "sh /path/to/myscript.sh"
with this:
sudo -u devops -H sh -c "sh /path/to/myscript.sh"
The -c option of su doesn't support interactive mode:
-c, --command COMMAND Specify a command that will be invoked by
the shell using its -c.
The executed command will have no controlling terminal. This option
cannot be used to execute interractive programs which need a
controlling TTY.
(man su)
By the way, I wouldn't use sudo within a script everywhere. The script might simply require root permissions. Within the script you might drop privileges where necessary by means of the above-mentioned sudo command.
I am creating a script meant to be run as superuser that reads a file and runs a number of scripts on behalf of all users. The important bit is this:
sudo -u $user -H source /home/$user/list_of_commands
However, whether I encose the command with quotesor not, this fails with:
sudo: source /home/user/list_of_commands: command not found
I have even tried with the . bash builtin:
sudo: . /home/user/list_of_commands: command not found
Of course running source outside a sudo environment works. I thought there might be a PATH problem, and I tried to bypass it by providing the full path to source. However, I cannot find the executable: which source returns which: no source in (/usr/local/sbin:usr/local/bin:usr/bin). So I'm stuck.
How do I make a script source a file as a user?
source is a builtin not a command, use it with bash -c:
sudo -u $user -H bash -c "source /home/$user/list_of_commands"
When I changed my current user to admin using
sudo su admin
I found that the environment variable changed too. What I intend to do is to change my user to admin with the env not changed.
Then I found a command as follows:
sudo bash -c "su - admin"
This command does indeed what I want, but I googled about bash -c, with no clue to why this command can do that for me. Could anyone give me a clear explanation? Thanks a lot.
first you should read the sudo manpage and set theses options in the /etc/sudoers file or you can do it interactively (see second below).
default sudoers file may not preserve the existing $USER environment unless you set the config options to do so. You'll want to read up on env_reset because depending on your OS distribution the sudo config will be different in most cases.
I dont mean to be terse but I am on a mobile device..
I do not recommend using sudo su .. for anything. whomever is sharing sudo su with the public is a newb, and you can accomplish the same cleaner with just sudo.
with your example whats happining is you are starting a subshell owned by the original user ("not admin") . you are starting the subshell with -c "string" sudo has the equivelant of the shell's -c using -s which either reads the shell from the arg passed to -s or the shell defined in the passwd file.
second you should use:
$ sudo -u admin -E -s
much cleaner right ? :)
-u sets the user, obviously
-s we just explained
-E preserves the orig user env
see for yourself just
$ echo $HOME # should show the original users /home/orig_user
$ env
your original env is preserved with none of that sudo su ugliness.
if you were interested in simulating a users login without preserving the env..
$ sudo -u user -i
or for root:
Might require -E depending on distro sudoers file
$ sudo -s
or
$ sudo -i
-i simulates the login and uses the users env.
hopefully this helps and someone will kindly format it to be more readable since im on my mobile.
bash with -c argument defines below.
-c string
If the -c option is present, then commands are read from string. If there are arguments after the string, they are assigned to the positional parameters, starting with $0.
Thanks & Regards,
Alok