`/REGEXP/'
This will select any line which matches the regular expression
REGEXP. If REGEXP itself includes any `/' characters, each must
be escaped by a backslash (`\').
The empty regular expression `//' repeats the last regular
expression match (the same holds if the empty regular expression is
passed to the `s' command). Note that modifiers to regular
expressions are evaluated when the regular expression is compiled,
thus it is invalid to specify them together with the empty regular
expression. 作者: sunzhiguolu 时间: 2016-08-21 02:01
perl -ne 'BEGIN{open(b,'b')}{chomp;print $_,scalar <b>}' a