Question

请问有人解释下面脚本的含义吗？

awk -F "," 's != $1 || NR ==1{s=$1;if(p){print p};p=$0;next}
            {sub($1,"",$0);p=p""$0;}
            END{print p}' file

该文件包含以下数据：

2,"URL","website","aaa.com"
2,"abc","text","some text"
2,"Password","password","12345678"
3,"URL","website","10.0.10.75"
3,"uname","text","some text"
3,"Password","password","password"
3,"ulang","text","some text"
4,"URL","website","192.168.2.110"
4,"Login","login","admin"
4,"Password","password","blah-blah"

，输出为：

2,"URL","website","aaa.com","abc","text","some text",Password","password","12345678"
3,"URL","website","10.0.10.75","uname","text","some text""Password","password","password","ulang","text","some text"

Answer 1

awk有这种结构

pattern {action}

对于你的脚本，让我们分析元素，第一个模式

 s != $1 || NR == 1   # if the variable s is not equal to first field
                      # or we're operating on first row

第一个动作

 s = $1   # assign variable s to first field
 if (p) {  # if p is not empty, print
     print p
 }
 p = $0    # assign the current line to p variable
 next      # move to next, skip the rest

缺少下一个模式，因此该操作将应用于所有行

 sub($1, "", $0)   # same as $1="", will clear the first field
 p = ((p "") $0)   # concat new line to p

最后一个模式是特殊保留字END，仅在消耗所有行时应用（在文件打开之前有应用的对应BEGIN）

 END {
      print p      # print the value of p
 }

使用awk合并文件中的行

1 个答案: