awk的结果有问题啊 晕

第二场雪

想获得用户名列表

1. [loveshell@Loveshell test]$ cat /etc/passwd|awk '{FS=":"} {print "user:"$1}'
   
2. user:root:x:0:0:root:/root:/bin/bash
   
3. user:bin
   
4. user:daemon
   
5. user:adm
   
6. user:lp
   
7. user:sync
   
8. user:shutdown
   
9. user:halt
   
10. user:mail
    
11. user:news
    
12. user:uucp
    
13. user:operator
    
14. user:games
    
15. user:gopher
    
16. user:ftp
    
17. user:nobody
    
18. user:vcsa
    
19. user:rpm
    
20. user:nscd
    
21. user:ident
    
22. user:netdump
    
23. user:sshd
    
24. user:rpc
    
25. user:rpcuser
    
26. user:nfsnobody
    
27. user:mailnull
    
28. user:smmsp
    
29. user:pcap
    
30. user:apache
    
31. user:ntp
    

复制代码

第一行的结果怎么也处理不了
但是用

1. [loveshell@Loveshell test]$ cat /etc/passwd|awk  -F : '{print "user:"$1}'
   
2. user:root
   
3. user:bin
   
4. user:daemon
   
5. user:adm
   
6. user:lp
   
7. user:sync
   
8. user:shutdown
   
9. user:halt
   
10. user:mail
    
11. user:news
    
12. user:uucp
    
13. user:operator
    
14. user:games
    
15. user:gopher
    
16. user:ftp
    
17. user:nobody
    
18. user:vcsa
    
19. user:rpm
    
20. user:nscd
    
21. user:ident
    
22. user:netdump
    
23. user:sshd
    
24. user:rpc
    
25. user:rpcuser
    
26. user:nfsnobody
    
27. user:mailnull
    
28. user:smmsp
    
29. user:pcap
    
30. user:apache
    
31. user:ntp
    
32. user:postfix
    

复制代码

正常了

寂寞烈火

awk 'BEGIN{FS=":"} {print "user:"$1}'

mjdcl

一般都是用-F指定分隔符