Learning how to bash script, questions.

Question

Hello everyone,
So I'm learning how to Bash script so I can improve my AUR packages, and also make some scripts for my personal use.
I've been working on a basic script that completely cleans your kernel source tree while saving your config file.
I was wondering if this is good and up to today's standards (Meaning checking existence of files, and checking return status for previous command):
#!/bin/bash
mv .config config
if [ -e "config" ] ; then
echo "Configuration has been backed up successfully."
else
echo "Error renaming, quitting program."
exit
fi
echo "Cleaning your kernel source tree!"
make distclean
if [ $? -eq 0 ]; then
echo "Your kernel source tree was clean successfully."
else
echo "Error cleaning your kernel source."
fi
mv config .config
if [ -e ".config" ] ; then
echo "Configuration has been installed successfully."
else
echo "Error renaming, quitting program."
exit
fi

Answer 1

What happens if you accidentally run it in your home directory? You probably don't want to be moving your .config folder around like this, even if it doesn't get hurt. Also, what happens if there's a pre-existing "config" file or folder? You should probably inform the user to deal with it, and bail out.
I would also consider using more verbosity, eg in the calls to "mv", and make the echo statements more descriptive and maybe use some colour.
In summary, if it were me, a first draft before playing with it more might look a bit like this:
#!/bin/bash
set -e
RED="\[\033[31m\]"
GREEN="\[033[32m\]"
BLUE="\[033[34m\]"
RESET_COLOURS="\[\033[0m\]"
CONFIG_FILE=".config"
BACKUP_FILE="config"
if [[ -f "$CONFIG_FILE" && ! -f "$BACKUP_FILE" ]]; then
printf "Backing up existing configuration: $BLUE"
mv -v "$CONFIG_FILE" "$BACKUP_FILE"
printf "${RESET_COLOURS}\n"
else
echo "Existing configuration not found or backup already exists, nothing to do."
exit
fi
printf "Cleaning kernel source tree in $(pwd) ... "
make distclean
if [ $? -eq 0 ]; then
printf "${GREEN}Success!${RESET_COLOURS}\n"
else
printf "${RED}Failed!${RESET_COLOURS}\n"
fi
if [[ -f "$BACKUP_FILE" && ! -f "$CONFIG_FILE" ]] ; then
printf "Restoring pre-existing configuration: $BLUE"
mv -v "$BACKUP_FILE" "$CONFIG_FILE"
printf "${RESET_COLOURS}\n"
else
echo "Backed up configuration not found or pre-existing configuration already there, nothing to do."
exit
fi
Last edited by /dev/zero (2012-01-13 23:03:10)