[SOLVED] Bash script delete (rm) permission denied

[malonn]

Hi all. I wrote the following bash script

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#!/bin/bash
if [[ ! $(sudo echo 0) ]]; then
	exit 1
	fi
# Directory names subject to change
echo Deleting Python files...
rm ~/.local/bin/*
rm -r ~/.local/lib/python3.10
rm -r /usr/local/lib/pkgconfig
rm -r /usr/local/lib/python3.10
rm /usr/local/lib/libpython3.10.a
rm cd /usr/local/bin/*
rm /usr/local/man
rm -r /usr/local/share/man

It is set as executable via the OS GUI. When I run it, the folders in the root directory do not get removed. It throws a permission denied error.
How can I get the script to remove those folders? The folders and files are removed just fine if I run directly via the terminal. What gives? Thanks.

[karlchen]

Hello, malonn.

The main question is:
What are you trying to achieve with this script?
Why do you not uninstall cleanly something, which you have installed previously following some installation instruction. Such instructions frequently also hold uninstallation instructions.

In case you assume that the initial if block makes sure that the script is run with root privileges: No, it does not.
As a consequence, all rm commands will very likely be run under your user account.
This would then explain why some fail due to missing permissions.

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rm /usr/local/lib/libpython3.10.a
rm cd /usr/local/bin/* ### <== what is the "cd" command doing in here?
rm /usr/local/man
rm -r /usr/local/share/man

And I seriously wonder whether it may not be a good thing that the rm commands fail.

Regards,
Karl

[rene]

As karlchen said, that initial if is wrong; it's testing output of sudo echo 0 and that output will always be not nul. Its attempted test is moreover superfluous: if you start the script from the menu as your user then your user is who runs it.

If you really want to do as you do start the script from the menus as e.g. pkexec /home/<user>/bin/script.sh (and without that initial if); this will request your admin password and run it elevated. However, it's a bit silly anyway: I'd suggest to just run e.g. sudo script.sh from the command-line for something like this.

On the command line the permission issues would by the way be no other -- and there's a rm cd and an rm /usr/local/man without an -r in there -- so no way that this runs "just fine" from a command line either, but in any case then, what you want is to start the script elevated through pkexec in a graphical context or plain old sudo in a command line one.

[AndyMH]

If you want to check if running as root:

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#check if running as root
if [ "$EUID" -ne 0 ]; then 
    echo "script needs to be run with sudo."
    exit
fi

[rene]

... and as I seem by and large unable to not point out in this context I tend to start scripts needing root with

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[ $(id -u) -eq 0 ] || exec sudo "$0" "$@"

which has them relaunch themselves via sudo if needed.

But note; this is here not relevant: sudo needs a terminal for one. From the menu's you'd like that pkexec.

[AndyMH]

Agreed, GUI use pkexec. If running from a GUI I'd want some visual indication of what it was doing, so either adding notify-send statements to the script or using zenity/yad for some popup windows.

[malonn]

Okay, thanks all. Some stuff to chew on here.
@karlchen, I wrote the script to remove old Python installation files. There is no installer/uninstaller. I build the files and install with "make altinstall"

@rene, I just wanted to double-click it and run it. Looks like your posts regarding pkexec are what I may need. I didn't really want to launch it from the menu. Also, I posted an old version of the script by accident. The working version cleans up any typos, etc.

@AndyMH, thanks. I still have a lot to learn about Linux and the terminal.

All things considered, what I want to do is set the script as executable, double-click it and run as admin. I may need pkexec for that, but I may just call it from the terminal as admin. I'll play around with it/search engine things some. You guys/gals put me on the right track.

[rigson23]

malonn,

I see your thread is noted as solved. May I just add a thought that you may or may not find helpful.

If your device is a home computer and given your desire to "double-click it and run as admin", have you considered passing the sudo password from a hidden password file (say .pswd) into your script via cat as in -

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cat .pswd | sudo -S rm ~/.local/bin/* && sudo rm -r ~/.local/lib/python3.10 etc

I use this for a couple of my own home maintenance scripts run via cron.

A less secure method would be putting the password into the script itself via echo as in -

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echo 123456 | sudo -S rm ~/.local/bin/* && sudo rm -r ~/.local/lib/python3.10 etc

where 123456 is your password for sudo.

So, in both cases, double-click and run with elevated privileges without user input.

[malonn]

No, I never thought of that. I'm a bash script/terminal noob, and haven't done much work with it.

Thanks for the tip.

[AndyMH]

have you considered passing the sudo password from a hidden password file

The better/modern way is to use polkits. Define a policy for your script that allows it to run without a password and run the script with pkexec.
Some basics here:
viewtopic.php?f=47&t=317804&p=1800030&h ... d#p1800030