Good idea. It works just fine with ksh. But note that it fails with bash if there are any leading 0s since bash will interpret a numeric string starting with 0 as octal instead of decimal.

If the OP is not willing to use ksh, we need to use a loop to strip leading 0s, use non-standard parameter expansions available in some shells that use REs instead of filename patterns, or use something like awk to process the ls output instead of the shell.

The following should work with any POSIX conforming shell:

Code:

off=${1:-30}
ls -r ANI_WFMASS_PIST*.gif | while IFS='T.' read -r f num t
do	# Strip leading zeroes from old number...
	if [ "$num" = "00000" ]
	then	old=0
	else	old="$num"
		while [ "$old" != ${old#0} ]
		do	old="${old#0}"
		done
	fi
	# Comput new number...
	new=$(printf '%05d' "$((old + off))")
	echo mv "${f}T$num.$t" "${f}T$new.$t"
done

And, again, if this produces the correct mvcommands, remove the echo shown in red.