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An example of how to use bash getopts
#!/bin/bash
######################################################################
#This is an example of using getopts in Bash. It also contains some
#other bits of code I find useful.
#Author: Linerd
#Website: http://tuxtweaks.com/
#Copyright 2014
#License: Creative Commons Attribution-ShareAlike 4.0
#http://creativecommons.org/licenses/by-sa/4.0/legalcode
######################################################################
#Set Script Name variable
SCRIPT=`basename ${BASH_SOURCE[0]}`
#Initialize variables to default values.
OPT_A=A
OPT_B=B
OPT_C=C
OPT_D=D
#Set fonts for Help.
NORM=`tput sgr0`
BOLD=`tput bold`
REV=`tput smso`
#Help function
function HELP {
echo -e \\n"Help documentation for ${BOLD}${SCRIPT}.${NORM}"\\n
echo -e "${REV}Basic usage:${NORM} ${BOLD}$SCRIPT file.ext${NORM}"\\n
echo "Command line switches are optional. The following switches are recognized."
echo "${REV}-a${NORM} --Sets the value for option ${BOLD}a${NORM}. Default is ${BOLD}A${NORM}."
echo "${REV}-b${NORM} --Sets the value for option ${BOLD}b${NORM}. Default is ${BOLD}B${NORM}."
echo "${REV}-c${NORM} --Sets the value for option ${BOLD}c${NORM}. Default is ${BOLD}C${NORM}."
echo "${REV}-d${NORM} --Sets the value for option ${BOLD}d${NORM}. Default is ${BOLD}D${NORM}."
echo -e "${REV}-h${NORM} --Displays this help message. No further functions are performed."\\n
echo -e "Example: ${BOLD}$SCRIPT -a foo -b man -c chu -d bar file.ext${NORM}"\\n
exit 1
}
#Check the number of arguments. If none are passed, print help and exit.
NUMARGS=$#
echo -e \\n"Number of arguments: $NUMARGS"
if [ $NUMARGS -eq 0 ]; then
HELP
fi
### Start getopts code ###
#Parse command line flags
#If an option should be followed by an argument, it should be followed by a ":".
#Notice there is no ":" after "h". The leading ":" suppresses error messages from
#getopts. This is required to get my unrecognized option code to work.
while getopts :a:b:c:d:h FLAG; do
case $FLAG in
a) #set option "a"
OPT_A=$OPTARG
echo "-a used: $OPTARG"
echo "OPT_A = $OPT_A"
;;
b) #set option "b"
OPT_B=$OPTARG
echo "-b used: $OPTARG"
echo "OPT_B = $OPT_B"
;;
c) #set option "c"
OPT_C=$OPTARG
echo "-c used: $OPTARG"
echo "OPT_C = $OPT_C"
;;
d) #set option "d"
OPT_D=$OPTARG
echo "-d used: $OPTARG"
echo "OPT_D = $OPT_D"
;;
h) #show help
HELP
;;
\?) #unrecognized option - show help
echo -e \\n"Option -${BOLD}$OPTARG${NORM} not allowed."
HELP
#If you just want to display a simple error message instead of the full
#help, remove the 2 lines above and uncomment the 2 lines below.
#echo -e "Use ${BOLD}$SCRIPT -h${NORM} to see the help documentation."\\n
#exit 2
;;
esac
done
shift $((OPTIND-1)) #This tells getopts to move on to the next argument.
### End getopts code ###
### Main loop to process files ###
#This is where your main file processing will take place. This example is just
#printing the files and extensions to the terminal. You should place any other
#file processing tasks within the while-do loop.
while [ $# -ne 0 ]; do
FILE=$1
TEMPFILE=`basename $FILE`
#TEMPFILE="${FILE##*/}" #This is another way to get the base file name.
FILE_BASE=`echo "${TEMPFILE%.*}"` #file without extension
FILE_EXT="${TEMPFILE##*.}" #file extension
echo -e \\n"Input file is: $FILE"
echo "File withouth extension is: $FILE_BASE"
echo -e "File extension is: $FILE_EXT"\\n
shift #Move on to next input file.
done
### End main loop ###
exit 0
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