Help with small bash functions please.

lagagnon · 2010-06-23 04:02:43

I'm not much of a programmer and trying to write two silly little bash functions, both have problems.

1) function to mount a pen drive as a normal user, run xfe, then unmount the pen drive:

function pen(){
        echo "Insert Pen Drive into USB port now!"
        sleep 4
        sudo mount -t vfat /dev/sdb1 /media/pen
        xfe /media/pen
        umount /media/pen
}

Problem is the sudo thing does not work. It does not stop to ask for a password so fails in mounting. Ideas?

2) function to start dropbox daemon, load an OO spreadsheet, work on the spreadsheet and then when OO closes kill the dropbox daemon. However, below does not work as expected, last line gets executed before OO shuts down. Why?

facah(){
        dropboxd &
        cd ~/Dropbox/facah
        sleep 6 && oocalc facah_db.ods
        kill `pidof dropbox`
}

ewaller · 2010-06-23 04:25:13

lagagnon wrote:

1) function to mount a pen drive as a normal user, run xfe, then unmount the pen drive:
function pen(){
        echo "Insert Pen Drive into USB port now!"
        sleep 4
        sudo mount -t vfat /dev/sdb1 /media/pen
        xfe /media/pen
        umount /media/pen
}
Problem is the sudo thing does not work. It does not stop to ask for a password so fails in mounting. Ideas?

Change the owner of the file to root, use chmod to make it executable by others and set the SUID. Make use the file is not writable by anyone but the owner (root). When a normal user executes the file, it will run with root privileges. This might not do everything you want. It might run xfe as root. I'm not sure. Never-the-less, you will need root privileges for the dismount.

ewaller · 2010-06-23 04:36:24

lagagnon wrote:

2) function to start dropbox daemon, load an OO spreadsheet, work on the spreadsheet and then when OO closes kill the dropbox daemon. However, below does not work as expected, last line gets executed before OO shuts down. Why?
facah(){
        dropboxd &
        cd ~/Dropbox/facah
        sleep 6 && oocalc facah_db.ods
        kill `pidof dropbox`
}

The && says "Execute command 1. If, and only if it returns 0 then execute command 2.

Your code is changing directories, waiting 6 seconds, then launches oocalc, which seems to always return 0 after the file opens. Note that oocalc returns 0 after the file opens, but the GUI and the spreadsheet remain open and detaches from the shell (killing the shell does not kill OOcalc)

igndenok · 2010-06-23 04:40:44

Maybe it should be like this

sudo mount -t vfat /dev/sdb1 /media/pen && xfe /media/pen && umount /media/pen

Run xfe if sudo mount return 0 and umount if xfe return 0
But, it's just my thought...

ber_t · 2010-06-23 05:51:41

ewaller wrote:

Change the owner of the file to root, use chmod to make it executable by others and set the SUID. Make use the file is not writable by anyone but the owner (root). When a normal user executes the file, it will run with root privileges. This might not do everything you want. It might run xfe as root. I'm not sure. Never-the-less, you will need root privileges for the dismount.

The kernel ignores the SUID bit on files starting with '#!'.

EDIT: You could use pmount to mount and unmount the drive as a normal user without using sudo.

Last edited by ber_t (2010-06-23 05:54:53)

tomk · 2010-06-23 05:54:19

Use pmount instead of mount.

lagagnon · 2010-06-23 15:34:21

ewaller wrote:

Note that oocalc returns 0 after the file opens, but the GUI and the spreadsheet remain open and detaches from the shell (killing the shell does not kill OOcalc)

You're absolutely right. Thanks for pointing that out. What I think I need to do is have an if test before the kill statement to check whether OO has yet been shut down, or if the spreadsheet file has been changed and then stop the dropbox daemon...

ewaller · 2010-06-23 16:29:29

ber_t wrote:

The kernel ignores the SUID bit on files starting with '#!'.

I checked, and you are correct. How did I miss that ? I am sure I have done this in the past. It must have been a binary. I know it worked on a Solaris system I used.

I learn something new every day.

lagagnon · 2010-06-23 16:38:37

tomk wrote:

Use pmount instead of mount.

That worked. Thanks!

Arch Linux

#1 2010-06-23 04:02:43

Help with small bash functions please.

#2 2010-06-23 04:25:13

Re: Help with small bash functions please.

#3 2010-06-23 04:36:24

Re: Help with small bash functions please.

#4 2010-06-23 04:40:44

Re: Help with small bash functions please.

#5 2010-06-23 05:51:41

Re: Help with small bash functions please.

#6 2010-06-23 05:54:19

Re: Help with small bash functions please.

#7 2010-06-23 15:34:21

Re: Help with small bash functions please.

#8 2010-06-23 16:29:29

Re: Help with small bash functions please.

#9 2010-06-23 16:38:37

Re: Help with small bash functions please.

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