精通正则表达式读书笔记

1.确定文件中ResetSize出现的次数与SetSize出现的次数是否相同

 perl -One 'print "$ARGV\n" if s/ResetSize//ig != s/SetSize//ig'

2 检查某个变量是否全部由数字构成

print "enter a temperature in celsius\n";$celsius = <STDIN>;chmop($celsius);if ($replay =~ m/^[0-9]+$/){    $fahrenheit = ($celsius * 9/ 5) + 32    print "$celsius C is  $fahrenheit F\n";}else{    print "expand a number,so i do not understand \"$fahrenheit\".\n";}

m表示正则表达式匹配regular expression match