awk 命令1

服务器上运行了多个 was server，要查全部 server 的进程 ID及 server name，不要中间一大段命令参数

ps -ef | grep java | awk '{print $2,$NF}'

:split
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awk 变量： 来源 AIX 5.3 man

  $0  recode, $1 $2 ~=  split var

NF NR 在不同的段落下意义不同。

    NF
            The number of fields in the current record, with a limit of 99. Inside a BEGIN action, the NF special variable is undefined unless a getline function without a Variable parameter has been issued previously. Inside an END action, the NF special variable retains the value it had for the last recordread, unless a subsequent, redirected, getline function without a Variable parameter is issued prior to entering the END action.

  NR
            The number of the current input record. Inside a BEGIN action the value of the NR special variable is 0 (zero). Inside an END action, the value is the number of the last record processed.

echo ab cd 12 34 | awk '{print $NR, $NF}'

结果是 ab 34

单行命令是 END action


:end