Shell Programming and Scripting

a=$(basename $(ls file*.csv) .csv); printf file_%0.8d.csv $(( ${a##*_} + 1))
file_00000002.csv

printf file_%0.8d.csv $(( $(ls file*.csv|tr -d '[:alpha:][:punct:]') + 1 ))

printf file_%0.8d.csv $(( $(ls file*.csv|tr -d '[:alpha:][:punct:]') + 1 ))

-bash-3.00$ printf file_%0.8d.csv $(( $(ls file_00000001.cvs |tr -d '[:alpha:][:punct:]') + 2 ))
file_00000003.csv-bash-3.00$

#!/usr/bin/ksh
# test:
# touch file_00000001.cvs file_00000002.cvs

# last file*.cvs file
last=$( ls -1 file*.cvs 2>/dev/null  | tail -1 )

# remove all a-z . and _ from filename
last=${last//[a-z_.]}

# if empty = no files => 1st file
[ "$last" = "" ] && last=0 # 1st file

((new=last+1))
newname=$(printf "file_%0.8d.cvs" $new)
do_something > $newname

[ ! -f last.txt ] && echo "0" > last.txt # 1st id
read last < last.txt

((new=last+1))
newname=$(printf "file_%0.8d.cvs" $new)
# save id
echo "$new" > last.txt
# 
do_something > $newname