Shell Script Question: Detect/Wait for USB Stick to be Ready

RobertKaucher · August 2012

I have a POS Linux box, some older version of Open SUSE, and I have a script that unmounts the USB thumb drive, formats it, and then waits for the device to become ready again before it runs a script that does a copy/MD5 checksum verification on the source and destination file to ensure the copy was valid. The problem is that on one box the USB thumb drive does not become ready after the format in a consistent way. I takes anywhere from 1 to 2+ minutes before I can access the drive via /media/LABELNAME.

The direct path is /dev/sdb but, of course, I cannot access it directly via this path to copy the files. Here is my shell script as it stands:

#!/bin/bash
set -e
echo "Starting LABELNAME.\n\nUnmounting /dev/sdb/"
umount /dev/sdb
echo "Formatting /dev/sdb/"
mkfs.vfat -I -F32 -n "LABELNAME" /dev/sdb
echo "Waiting on remount..."
sleep 30
echo "Format complete. Running make master."
perl /home/labelname_master.20120830.pl

Any suggestions?

UnixGuy · September 2012

So for some reason on one of the boxes and format (mkfs) command takes more time? The reason could be anything, the box might be slow or the system is busy doing something else.

How about giving it more time by increasing the "sleep 30" from 30 seconds to say, 90 seconds (sleep 90) ?

dontstop · September 2012

#!/bin/bash
set -e
echo "Starting LABELNAME.\n\nUnmounting /dev/sdb/"
umount /dev/sdb
echo "Formatting /dev/sdb/"
mkfs.vfat -I -F32 -n "LABELNAME" /dev/sdb
echo "Waiting on remount..."
sleep 30
echo "Format complete. Running make master."
perl /home/labelname_master.20120830.pl

Any suggestions?

S_DIR is the Directory that your drive mounts as i.e. /media/LABELNAME

This will loop until it finds the mounted drive file.

#!/bin/bash


S_DIR="/tmp/hereiam.file"


while [ `stat ${S_DIR} 2>/dev/null 1>&2; echo $?` -ne 0 ]
do
        sleep 1
        echo "Not found yet :)"
done

Shell Script Question: Detect/Wait for USB Stick to be Ready

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