求助：提取两文件共有的:name及其下方关联行的Bash实现

问题 #

现有两个输入文件，需提取两文件中共同的:name条目，同时输出file1中该:name下方所有的./name/of/file格式的行。尝试了如下awk命令：

awk '/:name1/{flag=1} flag;/ /{flag=0}' /path/of/input/file1

但该命令仅能输出第一个关联行，无法获取全部内容。

输入文件1 #

:name1
./name/of/file [logfile] [ error in file coming since Day : 1 ]
./name/of/file [logfile] [ error in file coming since Day : 1 ]

:name2
./name/of/file [logfile] [ error in file coming since Day : 1 ]

:name3
./name/of/file [logfile] [ error in file coming since Day : 24 ]
./name/of/file [logfile] [ error in file coming since Day : 24 ]

:name4
./name/of/file [logfile] [ error in file coming since Day : 3 ]
./name/of/file [logfile] [ error in file coming since Day : 3 ]
./name/of/file [logfile] [ error in file coming since Day : 3 ]
./name/of/file [logfile] [ error in file coming since Day : 3 ]

:name5
./name/of/file [logfile] [ error in file coming since Day : 6 ]
./name/of/file [logfile] [ error in file coming since Day : 6 ]

输入文件2 #

:name1
:name3
:name4

当前输出 #

:name1
    ./name/of/file [logfile] [ error in file coming since Day : 1 ]

期望输出 #

:name1
    ./name/of/file [logfile] [ error in file coming since Day : 1 ]
    ./name/of/file [logfile] [ error in file coming since Day : 1 ]
:name3
    ./name/of/file [logfile] [ error in file coming since Day : 24 ]
    ./name/of/file [logfile] [ error in file coming since Day : 24 ]
:name4
    ./name/of/file [logfile] [ error in file coming since Day : 3 ]
    ./name/of/file [logfile] [ error in file coming since Day : 3 ]
    ./name/of/file [logfile] [ error in file coming since Day : 3 ]
    ./name/of/file [logfile] [ error in file coming since Day : 3 ]

解决方案 #

原命令的问题在于/ /{flag=0}会匹配所有包含空格的行，而目标文件行本身就有空格，导致只输出第一行就关闭了输出标志。正确的思路是先将file2中的所有目标:name存入数组，再遍历file1，根据当前行是否属于目标name来控制输出。

命令实现 #

如果不需要缩进，使用以下命令：

awk 'NR==FNR {names[$0]=1; next} /^:/ {current=$0; print_flag=names[current]?1:0} print_flag && /^(\.\/|:/)' file2 file1

如果需要和期望输出一致的缩进格式，使用这个命令：

awk 'NR==FNR {names[$0]=1; next} /^:/ {current=$0; print_flag=names[current]?1:0; if(print_flag) print $0} print_flag && /^\.\// {print "    " $0}' file2 file1

命令说明 #

• NR==FNR {names[$0]=1; next}：处理file2时，将每一行的:name存入names数组，然后跳过后续逻辑，继续读取下一行。
• /^:/ {current=$0; print_flag=names[current]?1:0; if(print_flag) print $0}：在file1中遇到以:开头的行时，更新当前name，判断该name是否在names数组中，设置输出标志print_flag；如果是目标name，直接输出该行。
• print_flag && /^\.\// {print " " $0}：当输出标志为1时，对所有以./开头的行添加4个空格缩进后输出。

内容的提问来源于stack exchange，提问作者aastha