UNIX for Dummies Questions & Answers

3a3b4c

aaabbbcccc

$ cat input
3a3b4c
4a5d2c
10a12b14c
3abc4xyz5pqr
$
$ perl -ne 'chomp;print$2x$1while(/(\d+)(\D+)/g);print"\n"' input
aaabbbcccc
aaaadddddcc
aaaaaaaaaabbbbbbbbbbbbcccccccccccccc
abcabcabcxyzxyzxyzxyzpqrpqrpqrpqrpqr
$

############################RunLength_Decode###################################
#
#Implementatin of RunLength Decoding
#Written on:19March 11AM
#Author:Pandeeswaran
###############################################################################
#!/bin/bash
len=`echo $1|wc -c`
a=$1
for((i=0;i<=$len-1;i++))
do
ch=${a:$i:1}
echo $ch
if [ "${ch}" -eq "3" -o "${ch}" -eq "4" ]
then
res=${ch}
else
res=`echo "$res",`
fi
done

pandeeswaran@ubuntu:~/training$ bash RunLength_decode 3a
3
a
RunLength_decode: line 14: [: a: integer expression expected

RunLength_decode: line 14: [: : integer expression expected
pandeeswaran@ubuntu:~/training$

 
if [ "${ch}" -eq "3" -o "${ch}" -eq "4" ]

 
if [ "${ch}" = "3" -o "${ch}" = "4" ]
 
OR 
 
if [ ${ch} -eq 3 -o ${ch} -eq 4 ]