What do you think of my Bash Script? What about the error checking?

Question

Well what do you think of this Bash script
It works
I gave it some problems (i.e. unpluged the ethernet, messed up the URL's, uninstaled some programs...) to see if would report errors and stop or just keep going... But it did
I just kind of thought up a way to do some error checking with the commands that I know.....
What is a better way to do error checking?
What do you think I should add/Do to this script?
#!/bin/bash
# Shell script to make a USB Tumb Drive for Flashing BIOS on a Lenovo Ideapad Y510.
# This script needs to be owned and run as ROOT with the "sudo command"
# i.e. sudo usbbiosflasher
# If you have anyideas send me a PM on ubuntufourms.org my user name is HunterThomson
# Name/Rename this script usbbiosflasher and save it to the ~/home directory.
# Then run the command- chown root:root usbbiosflasher
# Then run the command- chmod 755 usbbiosflasher
# Then copy the script to the directory /usr/bin.
# Run this comand to do that- sudo cp ~/usbbiosflasher /usr/bin
# You also must have the program "mbr" installed
# You can install the mbr program by running this comand in the shell on Ubuntu
# sudo apt-get install mbr
# In Arch Linux you have to get it from Aur
# First you will need to know a few things...
# You will also need to know the Mount Point i.e. /media/disk and the /dev path i.e. /dev/sdb1.
# You can find these by using the df -T comand.
# Run df -T in the shell. Then plug in the USB Thumb Drive and run the df -T comand agin.
# The new listing is the USB Thumb Dirve.
# Also check to make sure the File System tipe is vFAT or FAT16 or FAT32.
# If it is not use gparted to format it to FAT32.
# I am farly certen that all USB Thumb drives come formated with FAT file system out of the BOX.
# You may want to fromat it anyway just to make sure.
echo "Interactive Shell Script to Make a USB Thumb Drive \for Flashing BIOS On a Lenovo Ideapad Y510"
echo ""
echo "You will need to have the program mbr installed"
echo "If you are on Ubuntu Linux you can retreve it form the repositories"
echo "If you are on Arch Linux you will need to get it from the Aur repository"
echo "Open anuther shell and \do that now..."
echo ""
verify="n"
while [ "$verify" != y ]
do
printf "Do you have mbr installed... yes or no?"
read AN1
echo ""
printf "You answered... $AN1 I have installed mbr. Is this correct... y or n?"
read verify
done
echo ""
if [ "$AN1" == "no" ]
then
echo "Install mbr now. Then run this script agin"
exit
else
echo "contunuing script"
fi
echo ""
# The next comand will make a directory to put needed files into. Note this file and everything init will be owned by root.
mkdir ~/usbbiosfiles && check1="yes"
if [ "$check1" = "yes" ]
then
echo "Made directory usbbiosfiles... OK"
else
echo "Could not \make directory usbbiosfiles"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
exit
fi
# The next two comands will get the FreeDOS file and the .ROM file.
cd ~/usbbiosfiles && checka="yes"
if [ "$checka" = "yes" ]
then
echo "Changing to the usbbiosfiles directory... OK"
else
echo "Could not Change to the usbbiosfiles directory"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
wget "http://www.fdos.org/bootdisks/autogen/FDOEM.144.gz" && check2="yes"
if [ "$check2" = "yes" ]
then
echo "Download of FreeDOS... OK"
else
echo "Could not Download FreeDOS"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
wget "http://ubuntuforums.org/attachment.php?attachmentid=78460&d=1216648756" && check3="yes"
if [ "$check3" = "yes" ]
then
echo "Download of the BIOS.ROM \file... OK"
else
echo "Could not Downlad the BIOS.ROM \file"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
# The next comand will name the .ROM file to the right name.
mv ~/usbbiosfiles/attachment.php?attachmentid=78460\&d=1216648756 ~/usbbiosfiles/06CN29WW.bios.update.tar.bz2 && check4="yes"
if [ "$check4" = "yes" ]
then
echo "Renameing of the BIOS.ROM \file... OK"
else
echo "Could not rename the BIOS.ROM \file"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
echo ""
# The next two comands set the variables. DEVX for the path i.e. /dev/xxx and MOUNTX for the mount point i.e. /media/xxx
verify="n"
while [ "$verify" != y ]
do
echo "You will need to know the Mount Point and the dev Path. You will also need to \make sure the File System \type is vFAT, FAT16 or FAT32."
echo ""
echo "With the USB Thumb Drive unpluged, Open another shell and run the comand df -T Then plug \in the USB Thumb Drive and run the comand df -T one \more time. The new device listed is the USB Thumb Drive. Note the Mount Point and The dev Path and the File system Type i.e. vFAT... If the File System \type is not vFAT, FAT16 or FAT32 you will need to fromat it with gparted. You may want to format the USB Thumb Drive anyway just to \make sure. In any \case delete all files and directorys on the USB drive before you go any ferther with this program."
echo ""
printf "Enter the dev path the USB Thumb Drive is at?"
read DEVX
echo ""
echo "Are you sure $DEVX is the dev path of the USB Thumb Drive... y or n?"
read verify
done
echo ""
verify="n"
while [ "$verify" != y ]
do
printf "What is the Mount Point of the USB Thumb Drive?"
read MOUNTX
echo ""
echo "Are you sure $MOUNTX is the Mount Point of the USB Drive... y or n?"
read verify
done
echo ""
install-mbr --enable A1 --partition 1 --force --timeout 0 $DEVX && check5="yes"
if [ "$check5" = "yes" ]
then
echo "Installing MBR on USB Thumb Dirve... OK"
else
echo "Could not install MBR on USB Thumb Drive"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
tar xjf ~/usbbiosfiles/*.tar.bz2 && check7="yes"
if [ "$check7" = "yes" ]
then
echo "Unpacking BIOS.ROM file... OK"
else
echo "Could not unpack BIOS.ROM file"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
gunzip ~/usbbiosfiles/FDOEM.144.gz && check8="yes"
if [ "$check8" = "yes" ]
then
echo "Unpacking FreeDOS files... OK"
else
echo "Could not unpack FreeDOS files"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
mkdir ~/usbbiosfiles/fdoem144 && check9="yes"
if [ "$check9" = "yes" ]
then
echo "Made directory fdoem144 in direcoty usbbiosfiles... OK"
echo ""
echo "Going to \sleep \for 5secs"
else
echo "Could not make directory fdoem144 in usbbiosfiles directory"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
modprobe loop && sleep 5 && check0="yes"
if [ "$check0" = "yes" ]
then
echo "Modprobeing loop... OK"
else
echo "Could not \modprobe loop"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
mount -o loop ~/usbbiosfiles/FDOEM.144 ~/usbbiosfiles/fdoem144 && check10="yes"
if [ "$check10" = "yes" ]
then
echo "Mounting FreeDOS on the fdoem144 directory... OK"
else
echo "Could not \mount FreeDOS on the fdoem144 directory"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
cp ~/usbbiosfiles/fdoem144/* $MOUNTX && check11="yes"
if [ "$check11" = "yes" ]
then
echo "Copying FreeDOS files to $MOUNTX... OK"
else
echo "Could not copy FreeDOS files to $MOUNTX"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
cp ~/usbbiosfiles/*.ROM $MOUNTX && check12="yes"
if [ "$check12" = "yes" ]
then
echo "Copying BIOS.ROM files to $MOUNTX... OK"
else
echo "Could not copy BIOS.ROM files to $MOUNTX"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
sync && check13="yes"
if [ "$check13" = "yes" ]
then
echo "Runing the syncing command... OK"
else
echo "Could not run the syncing command"
echo "look above \for \info"
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this scrip agin"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
rm -r ~/usbbiosfiles
exit
fi
umount ~/usbbiosfiles/fdoem144 && check14="yes"
if [ "$check14" = "yes" ]
then
echo "Unmounting of FreeDOS... OK"
else
echo "Could not unmount FreeDOS"
echo "Look above for errors or problems reported and fix the problem"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this script agin"
rm -r ~/usbbiosfiles
exit
fi
verify="n"
while [ "$verify" != y ]
do
printf "Do you see any errors... yes or no?"
read AN2
echo ""
printf "You answered... $AN2 to errors. Is this correct... y or n?"
read verify
done
echo ""
if [ "$AN2" == "yes" ]
then
echo "User Repoted... Error"
echo "Look above for errors or problems reported and fix the problem"
echo ""
echo "removeing directory usbbiosfiles..."
echo ""
echo "Reformat the USB Stick to FAT32 with gparted"
echo "Fix the problem and run this script agin"
rm -r ~/usbbiosfiles
exit
else
echo "Success"
echo "I did a lot of error checking too and didnt find anything"
echo ""
echo "Go get a pen and paper to write down these instructions"
printf "Then hit the Enter to continue"
read WAIT
echo ""
echo "Now leave the USB Thumb Drive pluged into your computer and Reboot. When the Lenovo Logo POST screen appears hit F2 to enter the CMOS setup utility. Go over to BOOT tab and go down to HardDrive \(Not Boot Order) \then \select the USB Thumb Drive as the 1st hard drve. Then F10 and yes to save changes. Your compter will reboot agin. Then when the Lenovo Logo POST Screen appers on reboot hit F4 to enter the BIOS FLASHING program. The USB Thumb Drive will be seen as the C drive \in the list on the Left, Select it. Then \select the .ROM \file \in the list on the Right and start the BIOS FLASH. \(NOTE Your hart may stop beating... This is normal) Pray to any God you know of and your computer should restart just like normal. Hit F2 and the BIOS will now stay it is 06CN29WW. You will need to \set the boot order to the way you like it and other things \if you need to because they have been changed to the default."
fi
echo ""
echo "End of script"
Last edited by hunterthomson (2008-08-10 11:17:47)

Answer 1

Personally.....  (this is just how I would have written it - if it works, then it's good enough for me though )
I would change this whole block:
verify="n"
while [ "$verify" != y ]
do
printf "Do you have mbr installed... yes or no?"
read AN1
echo ""
printf "You answered... $AN1 I have installed mbr. Is this correct... y or n?"
read verify
done
echo ""
if [ "$AN1" == "no" ]
then
echo "Install mbr now. Then run this script agin"
exit
else
echo "contunuing script"
fi
To this much shorter code:
MBR='/usr/bin/install-mbr' # Or where ever you expect it to be
if [ ! -x $MBR ] ; then
echo "mbr doesn't appear to be installed."
echo "If it is installed, check it's location, make sure it's executable and then make sure the MBR variable in this script is correct"
exit 1
fi
I wouldn't have used the checkXX variables for each stage:
mkdir ~/usbbiosfiles
if [ $? != 0 ] ; then
#failed
echo "Could not \make directory usbbiosfiles"
echo "look above \for \info"
echo "Fix the problem and run this scrip agin"
exit 1
else
echo "Made directory usbbiosfiles... OK"
fi
There is an issue with the way you do your verifications - the user can never get out unless they answer 'y' or hit CTRL+C. Something like this gives them options:
verify="n"
while [ "$verify" != "y" && "$verify" != "n" ]; do
echo "You need to answer 'y'es or 'n'o"
read verify
echo $verify | tr "[:upper:]" "[:lower:]" # This converts the answer to lowercase so replies entered in upper case will still work
done
if [ $verify != 'y' ] ; then
exit 1
fi
One last thing I try to do in scripts... Declare all your binaries as variables at the start of the program, then execute the binary program by using the variable. For example:
# Binaries
TAR='/bin/tar'
CP='/bin/cp'
CHMOD='/bin/chmod'
# Execute tar and chmod the created file
$TAR cvzf /tmp/tarfile.tar.gz /etc/*.conf
$CHMOD 400 /etc/*.conf
This way, it's easy to change the path in future without having to hunt through the script if the paths change, and it also ensures you're calling the programs using the full paths to make sure you're not executing some strange variant or alias that someone has setup. If I use `chmod` 30 times in a script, and the path changes in the future or on a different system (`chmod` is a bad example cause it's highly unlikely to change, but you know what I mean), then all you need to do is update the variable at the start of the script, and it all works again without having to script-hunt and change it 30 times.