awk编程使用

使用awk命令，
对于/etc/passwd文件，分别统计uid小于100,uid在100-500之间，uid大于500的用户
统计分别使用ksh和bash的用户，
并且最后输出uid大于500的user的条目.

[root@demo ~]#  awk -F: '{
if($3>=0 && $3<100){i++}
else if($3>=100 && $3<500){j++}
else if($3>=500){user[k++]=$0}}
$7~/bash$|ksh$/{sum[$7]++}
END{
print "uid小于100个数:",i?i:0,"\nuid在100到500之间个数:",j?j:0,"\nuid大于500个数:",k?k:0;
for(m in sum){print m,sum[m]};
print "uid大于500的user如下：";
for(p=0;p<k;p++){print p,user[p]}
}' /etc/passwd

执行输出结果：
uid小于100个数: 36
uid在100到500之间个数: 0
uid大于500个数: 9
/bin/bash 6
/bin/ksh 3
uid大于500的user如下：
0 nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin
1 idsldap:x:500:500::/home/idsldap:/bin/ksh
2 dsrdbm02:x:502:502::/home/dsrdbm02:/bin/ksh
3 ldap2:x:503:503::/home/ldap2:/bin/ksh
4 dasusr1:x:505:103::/home/dasusr1:/bin/bash
5 db2inst1:x:506:104::/home/db2inst1:/bin/bash
6 db2fenc1:x:507:105::/home/db2fenc1:/bin/bash
7 test:x:510:510:test:/home/test:/bin/bash
8 fenced:x:511:511:fenced:/home/fenced:/bin/bash
[root@demo ~]#

查看上面输出统计数据与下面对比，上面脚本执行统计结果正确：
[root@demo ~]# cat /etc/passwd|wc -l
45
[root@demo ~]# cat /etc/passwd|grep ksh|nl
     1  idsldap:x:500:500::/home/idsldap:/bin/ksh
     2  dsrdbm02:x:502:502::/home/dsrdbm02:/bin/ksh
     3  ldap2:x:503:503::/home/ldap2:/bin/ksh
[root@demo ~]# cat /etc/passwd|grep bash|nl
     1  root:x:0:0:root:/root:/bin/bash
     2  dasusr1:x:505:103::/home/dasusr1:/bin/bash
     3  db2inst1:x:506:104::/home/db2inst1:/bin/bash
     4  db2fenc1:x:507:105::/home/db2fenc1:/bin/bash
     5  test:x:510:510:test:/home/test:/bin/bash
     6  fenced:x:511:511:fenced:/home/fenced:/bin/bash