Help me! Script bash

Susy · 02-06-2011, 08:19 AM

Hi guys,
I need help with my bash script.

I would like to find the name of my USB device, searching myFile.txt.

So using "mount" command I found all mounted devices, for example:

>mount

/dev/sda1 on /media/usb1 [...]
/dev/sdb1 on /media/usb2 [...]

I would like to verify if myFile.txt exists in /media/usb1 or in /media/usb2, but I don't know to traslate it in a bash code.

Thanks,

Susy

sycamorex · 02-06-2011, 08:24 AM

Hi and welcome to LQ.

The following code should get you started:

Code:

if [ -f /path/to/testfile ] 
then 
  echo "testfile exists!" 
else
  echo "testfile does not exist"
fi

If you don't know the exact location of your file, you might want to read on the 'find' command.
http://content.hccfl.edu/pollock/unix/findcmd.htm

catkin · 02-06-2011, 09:22 AM

Something like (not tested) ...

Code:

while read -a my_array
do
    find ${my_array[2]} -type f -iname myFile.txt
done <<< "$( mount | grep media )"

Susy · 02-06-2011, 01:03 PM

Thank you.

Tomorrow I'll try both solutions.

Nominal Animal · 02-06-2011, 01:55 PM

Your problem is actually locating the mounted device containing a specific file; sycamorex and catkin already answered that quite well.

I've had to solve a situation where the user should be able to select any USB storage device, whether or not it is mounted.
This is also easy to solve, without elevated privileges; you can find this out as a normal user without root access.
In case somebody reading this topic happens to need it, here's the code I've used:

Code:

#!/bin/bash
Device=()
Mounts=()
Name=()
Size=()
for node in /dev/sd[a-z] ; do
    dev="${node#/dev/}"
    removable=$[ `cat /sys/block/$dev/removable` -0 ]
    if [ $removable -eq 1 ]; then
        Device=("${Device[@]}" "$node")
        Mounts=("${Mounts[@]}" `grep -ce "^$node" /proc/mounts`)
        Name=("${Name[@]}" "`cat /sys/block/$dev/device/vendor` `cat /sys/block/$dev/device/model`")
        Size=("${Size[@]}" $[(`cat /sys/block/$dev/size`-0)/2])
    fi
done

i=0
while [ $i -lt ${#Device[@]} ]; do
    d=${Device[i]}
    m=${Mounts[i]}
    n=${Name[i]}
    s=${Size[i]}
    i=$[i + 1]
    echo "$d:"
    echo " Name: $n"
    echo " Size: $s kB"
    case $m in
        0) echo " Mounted: No" ;;
        1) echo " Mounted: Yes, 1 partition" ;;
        *) echo " Mounted: Yes, $m partitions" ;;
    esac
    echo ""
done

First part will fill in four parallel arrays: Device, Mounts, Name, and Size.
"${Device[0]}" is the device node for the first device,
${Mounts[1]} contains the number of partitions mounted on the second device, zero if none,
"${Name[0]}" is the vendor and model name for the first device, and
${Size[1]} is the size of the second device in kilobytes (1024 byte blocks).
The number of devices found is of course ${#Device[@]}.

The second part just outputs the list. Replace it with your own selection routines. I normally list one device per line, identified by a letter, and let the user select one or more devices by specifying their letters. Works quite reliably.

Hope this helps someone,

Nominal Animal