Shell Programming and Scripting

$ for i in seq {01..10}; do touch ${i}.txt; done

$ ./rename.sh *.txt txt tab

Error:
mv: ‘01.txt’ and ‘01.txt’ are the same file.

#!/usr/bin/bash 
# renames.sh 
# Usage: ./rename.sh regex match replacement 
 
pattern=$1 
match=$2 
replace=$3 
 
for i in $( ls *$pattern* );  
do 
 src=${i} 
 dst=$( echo ${i} | sed -e "s/${match}/${replace}/" ) 
 mv ${src} ${dst} 
done

for i in *.text*; do mv ${i} ${i%.text}.tab; done

$ ./rename.sh txt txt tab

$ ./rename.sh \.txt txt tab

./rename.sh "*.txt" txt tab

#!/bin/bash
printf '$#=%d\n$0="%s"\n' $# "$0"
cnt=$#
for((i = 1; i <= $cnt; i++))
do	printf '$%d="%s"\n' $i "$1"
	shift
done

./scriptname *.txt txt tab

./scriptname \*.txt txt tab

./scriptname "*.txt" txt tab

./scriptname '*.txt' txt tab

./scriptname "*".txt txt tab

./scriptname *".txt" txt tab