管線命令 (pipe)

• 管線命令的處理
  
  
  
  1. 使用cat指令輸出後的內容，以grep找出要看的字串。
     

     [root@kvm5 ~]# cat /tmp/auto.master | grep misc
     /misc	/etc/auto.misc
     # Note that if there are entries for /net or /misc (as
     

  2. 使用ls指令輸出後的內容，被less讀取，並且利用less的功能前後翻動相關的資訊。
     

     [root@kvm5 ~]# ls -al /etc | less
     

  3. Examples
     

     [root@kvm5 ~]# ls /usr/lib64 | grep 'libX11'
     libX11.so.6
     libX11.so.6.3.0
     libX11-xcb.so.1
     libX11-xcb.so.1.0.0
     
     [root@kvm5 ~]# grep '^n.*/sbin/nologin$' /etc/passwd
     nobody:x:99:99:Nobody:/:/sbin/nologin
     nscd:x:28:28:NSCD Daemon:/:/sbin/nologin
     nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin
     ntp:x:38:38::/etc/ntp:/sbin/nologin
     nslcd:x:65:55:LDAP Client User:/:/sbin/nologin
     
     [root@kvm5 ~]# grep '^n.*/sbin/nologin$' /etc/passwd | sort
     nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin
     nobody:x:99:99:Nobody:/:/sbin/nologin
     nscd:x:28:28:NSCD Daemon:/:/sbin/nologin
     nslcd:x:65:55:LDAP Client User:/:/sbin/nologin
     ntp:x:38:38::/etc/ntp:/sbin/nologin
     
     [root@kvm5 ~]# grep '^n.*/sbin/nologin$' /etc/passwd | sort | mail -s 'dywang test' root@kvm5.deyu.wang
     [root@kvm5 ~]# mail
     Heirloom Mail version 12.4 7/29/08.  Type ? for help.
     "/var/spool/mail/root": 2 messages 2 new
     >N  1 Mail Delivery System  Mon Jan 23 19:19  96/3452  "Undelivered Mail Returned to Sender"
      N  2 root                  Mon Jan 23 19:24  39/1643  "dywang test"
     & 2
     Message  2:
     From root@kvm5.deyu.wang  Mon Jan 23 19:24:16 2012
     Return-Path: <root@kvm5.deyu.wang>
     X-Original-To: root@kvm5.deyu.wang
     Delivered-To: root@kvm5.deyu.wang
     Date: Mon, 23 Jan 2012 19:24:16 +0800
     To: root@kvm5.deyu.wang
     Subject: dywang test
     User-Agent: Heirloom mailx 12.4 7/29/08
     Content-Type: text/plain; charset=us-ascii
     From: root@kvm5.deyu.wang (root)
     Status: R
     
     nfsnobody:x:65534:65534:Anonymous NFS User:/var/lib/nfs:/sbin/nologin
     nobody:x:99:99:Nobody:/:/sbin/nologin
     nscd:x:28:28:NSCD Daemon:/:/sbin/nologin
     nslcd:x:65:55:LDAP Client User:/:/sbin/nologin
     ntp:x:38:38::/etc/ntp:/sbin/nologin
     
     & q
     Held 2 messages in /var/spool/mail/root