第一章

while (<>) {
chomp;
print join ("	",(split /:/)[0,2,1,5]),"
";
}



[root@june3 perl]# cat a.txt 
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
[root@june3 perl]# perl 1.pl a.txt
root	0	x	/root
bin	1	x	/bin
daemon	2	x	/sbin
adm	3	x	/var/ad


#!/usr/bin/perl
##调用外部命令,输出结果一行行存入数组
@lines = `perldoc -u -f atan2`;
foreach (@lines){
 print "1-------$_
";
 s/w<([^>]+)>/U$1/g; 
 print "2---------$_
";
}