join

linux下的命令

用法：join [选项]... 文件1 文件2
For each pair of input lines with identical join fields, write a line to
standard output.  The default join field is the first, delimited
by whitespace.  When FILE1 or FILE2 (not both) is -, read standard input.

-a FILENUM        print unpairable lines coming from file FILENUM,where
                	FILENUM is 1 or 2, corresponding to FILE1 or FILE2
-e EMPTY          replace missing input fields with EMPTY
-i, --ignore-case  	ignore differences in case when comparing fields
-j FIELD          equivalent to `-1 FIELD -2 FIELD'
-o FORMAT         obey FORMAT while constructing output line
-t CHAR           use CHAR as input and output field separator
-v FILENUM        like -a FILENUM, but suppress joined output lines
-1 FIELD          join on this FIELD of file 1
-2 FIELD          join on this FIELD of file 2
--help     			显示此帮助信息并退出
--version  			输出版本信息并退出

注意：使用join应注意连接域到底是哪一个,比如说你认为正在访问域 4,但实际上join应该访问域5,这样将不返回任何结果。如果是这样,用 awk检查域号。例如,键入 $ awk '{print $4}'文件名,观察其是否匹配假想域;
$cat tt
-rwxr-xr-x 1 root root 1499 04-16 17:04 GC0204216.txt
-rw-r--r-- 1 root root  234 04-16 17:36 lxs
-rw-r--r-- 1 root root  322 04-16 17:51 temp
-rwxr--r-- 1 root root   83 04-16 08:24 test.sed
-rw-r--r-- 1 root root    0 04-16 18:25 tt
-rw-r--r-- 1 root root  283 04-16 18:07 ttt
$cat ttt
-rw-r--r-- 1 root root 550 14 07:34 df
-rw-r--r-- 1 root root 550 13 17:49 dir
-rw-r--r-- 1 root root 942 13 18:14 ifconfig
-rw-r--r-- 1 root root 550 07 17:59 ip
-rw-r--r-- 1 root root 85 14 08:24 strip
-rw-r--r-- 1 root root 394 14 00:13 tt
-rw-r--r-- 1 root root 272 16 07:19 ttt
$join -j1 8 -j2 8 tt ttt
tt -rw-r--r-- 1 root root 0 04-16 18:25 -rw-r--r-- 1 root root 394 14 00:13
ttt -rw-r--r-- 1 root root 283 04-16 18:07 -rw-r--r-- 1 root root 272 16 07:19
$join -a1 -j1 8 -j2 8 tt ttt
GC0204216.txt -rwxr-xr-x 1 root root 1499 04-16 17:04
lxs -rw-r--r-- 1 root root 234 04-16 17:36
temp -rw-r--r-- 1 root root 322 04-16 17:51
test.sed -rwxr--r-- 1 root root 83 04-16 08:24
tt -rw-r--r-- 1 root root 0 04-16 18:25 -rw-r--r-- 1 root root 394 14 00:13
ttt -rw-r--r-- 1 root root 283 04-16 18:07 -rw-r--r-- 1 root root 272 16 07:19