Shell Programming and Scripting

$
$ cat file.csv
"100","100","ABC"
"100","200","ABC"
"100","300","ABC"
$
$ # awk
$ awk -F, '{gsub(/"/,""); printf("\"%s\",\"%07s\",\"%s\"\n",$1,$2,$3)}' file.csv
"100","0000100","ABC"
"100","0000200","ABC"
"100","0000300","ABC"
$
$ # or perl
$ perl -ne '{chomp; split /","/; printf("%s\",\"%07s\",\"%s\n",$_[0],$_[1],$_[2])}' file.csv
"100","0000100","ABC"
"100","0000200","ABC"
"100","0000300","ABC"
$

#!/usr/bin/env python
import csv
filename = "file"
reader = csv.reader(open(filename))
writer = csv.writer( open("newfile.csv","wb"), quoting=csv.QUOTE_ALL)
for row in reader: 
    writer.writerow(row)

# ./test.py
# more newfile.csv
"100","0000100","ABC"
"100","0000200","ABC"
"100","0000300","ABC"