[linux] Execute a shell script in current shell with sudo permission

For executing a shell script in current shell, we need to use a period . or a source command. But why does it not work with a sudo permission?

I have a script with execute permission called setup.sh. When I use a period, I get this:

$ sudo . ./setup.sh 
sudo: .: command not found

The source command also produces a similar error. Am I missing out something? What should I do to run the script with sudo permission in the same shell?

Thanks in advance..

If you really want to "ExecuteCall a shell script in current shell with sudo permission" you can use exec to...

replace the shell with a given program (executing it, not as new process)

I insist on replacing "execute" with "call" because the former has a meaning that includes creating a new process and ID, where the latter is ambiguous and leaves room for creativity, of which I am full.

Consider this test case and look closely at pid 1337

# Don't worry, the content of this script is cat'ed below
$ ./test.sh -o foo -p bar

User ubuntu is running...
 PID TT       USER     COMMAND
 775 pts/1    ubuntu   -bash
1408 pts/1    ubuntu    \_ bash ./test.sh -o foo -p bar
1411 pts/1    ubuntu        \_ ps -t /dev/pts/1 -fo pid,tty,user,args

User root is running...
 PID TT       USER     COMMAND
 775 pts/1    ubuntu   -bash
1337 pts/1    root      \_ sudo ./test.sh -o foo -p bar
1412 pts/1    root          \_ bash ./test.sh -o foo -p bar
1415 pts/1    root              \_ ps -t /dev/pts/1 -fo pid,tty,user,args

Take 'exec' out of the command and this script would get cat-ed twice. (Try it.)

#!/usr/bin/env bash

echo; echo "User $(whoami) is running..."
ps -t $(tty) -fo pid,tty,user,args

if [[ $EUID > 0 ]]; then
    # exec replaces the current process effectively ending execution so no exit is needed.
    exec sudo "$0" "$@"
fi

echo; echo "Take 'exec' out of the command and this script would get cat-ed twice. (Try it.)"; echo
cat $0

Here is another test using sudo -s

$ ps -fo pid,tty,user,args; ./test2.sh
  PID TT       USER     COMMAND
10775 pts/1    ubuntu   -bash
11496 pts/1    ubuntu    \_ ps -fo pid,tty,user,args

User ubuntu is running...
  PID TT       USER     COMMAND
10775 pts/1    ubuntu   -bash
11497 pts/1    ubuntu    \_ bash ./test2.sh
11500 pts/1    ubuntu        \_ ps -fo pid,tty,user,args

User root is running...
  PID TT       USER     COMMAND
11497 pts/1    root     sudo -s
11501 pts/1    root      \_ /bin/bash
11503 pts/1    root          \_ ps -fo pid,tty,user,args

$ cat test2.src
echo; echo "User $(whoami) is running..."
ps -fo pid,tty,user,args

$ cat test2.sh
#!/usr/bin/env bash

source test2.src

exec sudo -s < test2.src

And a simpler test using sudo -s

$ ./exec.sh
bash's PID:25194    user ID:7809
systemd(1)---bash(23064)---bash(25194)---pstree(25196)

Finally...
bash's PID:25199    user ID:0
systemd(1)---bash(23064)---sudo(25194)---bash(25199)---pstree(25201)

$ cat exec.sh
#!/usr/bin/env bash

pid=$$
id=$(id -u)
echo "bash's PID:$pid    user ID:$id"
pstree -ps $pid

# the quoted EOF is important to prevent shell expansion of the $...
exec sudo -s <<EOF
echo
echo "Finally..."
echo "bash's PID:\$\$    user ID:\$(id -u)"
pstree -ps $pid
EOF

Basically sudo expects, an executable (command) to follow & you are providing with a .

Hence the error.

Try this way $ sudo setup.sh

The answers here explain why it happens but I thought I'd add my simple way around the issue. First you can cat the file into a variable with sudo permissions. Then you can evaluate the variable to execute the code in the file in your current shell.

Here is an example of reading and executing an .env file (ex Docker)

 sensitive_stuff=$(sudo cat ".env")
 eval "${sensitive_stuff}"
 echo $ADMIN_PASSWORD 

I think you are confused about the difference between sourcing and executing a script.

Executing a script means creating a new process, and running the program. The program can be a shell script, or any other type of program. As it is a sub process, any environmental variables changed in the program will not affect the shell.

Sourcing a script can only be used with a bash script (if you are running bash). It effectively types the commands in as if you did them. This is useful as it lets a script change environmental variables in the shell.

Running a script is simple, you just type in the path to the script. . is the current directory. So ./script.sh will execute the file script.sh in the current directory. If the command is a single file (eg script.sh), it will check all the folders in the PATH variable to find the script. Note that the current directory isn't in PATH, so you can't execute a file script.sh in the current directory by running script.sh, you need to run ./script.sh (unless the current directory is in the PATH, eg you can run ls while in the /bin dir).

Sourcing a script doesn't use the PATH, and just searches for the path. Note that source isn't a program - otherwise it wouldn't be able to change environmental variables in the current shell. It is actually a bash built in command. Search /bin and /usr/bin - you won't find a source program there. So to source a file script.sh in the current directory, you just use source script.sh.

How does sudo interact with this? Well sudo takes a program, and executes it as root. Eg sudo ./script.sh executes script.sh in a sub process but running as root.

What does sudo source ./script.sh do however? Remember source isn't a program (rather a shell builtin)? Sudo expects a program name though, so it searches for a program named source. It doesn't find one, and so fails. It isn't possible to source a file running as root, without creating a new subprocess, as you cannot change the runner of a program (in this case, bash) after it has started.

I'm not sure what you actually wanted, but hopefully this will clear it up for you.

Here is a concrete example. Make the file script.sh in your current directory with the contents:

#!/bin/bash    
export NEW_VAR="hello"
whoami
echo "Some text"

Make it executable with chmod +x script.sh.

Now observe what happens with bash:

> ./script.sh
david
Some text
> echo $NEW_VAR

> sudo ./script.sh
root
Some text
> echo $NEW_VAR

> source script.sh
david
Some text
> echo $NEW_VAR
hello
> sudo source script.sh
sudo: source: command not found

Easiest method is to type:

sudo /bin/sh example.sh

Even the first answer is absolutely brilliant, you probably want to only run script under sudo.

You have to specify the absolute path like:

sudo /home/user/example.sh
sudo ~/example.sh

(both are working)

THIS WONT WORK!

sudo /bin/sh example.sh
sudo example.sh

It will always return

sudo: bin/sh: command not found
sudo: example.sh: command not found

I'm not sure if this breaks any rules but

sudo bash script.sh

seems to work for me.