m4.sh

Shall高级编程

#!/bin/bash
# m4.sh: Using the m4 macro processor

# Strings
string=abcdA01
echo "len($string)" | m4                            #   7
echo "substr($string,4)" | m4                       # A01
echo "regexp($string,[0-1][0-1],\&Z)" | m4          # 01Z

# Arithmetic
echo "incr(22)" | m4                                #  23
echo "eval(99 / 3)" | m4                            #  33

exit 0