Shell Programming and Scripting

file="leadingzero.txt"     # input filename
while read line 
    do
        wardevent=${line##*[!1-9]}                     # remove leading Zero from the line
echo $wardevent
done <"$file"

001
002
003
004
005
006
007
008
009
010
011
012
019
020
021

 $ cat file
001
002
003
004
005
006
007
008
009
010
011
012
019
020
021

 $ awk '{$1+=0}1' file
1
2
3
4
5
6
7
8
9
10
11
12
19
20
21

 awk '{sub(/^0/,"")}1' file
01
02
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19
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21

$ awk '{$1+=0}1' file

#!/bin/ksh

typeset -i col1                     # Define as integer

while read col1 rest
do
   echo "$col1 $rest"
done < input_file  > output_file

while read line 
    do
        wardevent=$(expr $line + 0)                     # remove leading Zero from the line
echo $wardevent
done<file

0001
0002 123
0003 Hello