join命令可以讲多个相同字段的文件结合到一起
NAME
join - join lines of two files on a common field
SYNOPSIS
join [OPTION]... FILE1 FILE2
DESCRIPTION
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 display this help and exit
--version
output version information and exit
[root@linuxso.com shell]# cat tt1
test 100
test1 80
test2 90
[root@linuxso.com shell]# cat tt2
test yingyu
test1 shuxue
test2 yuwen
[root@linuxso.com shell]# join tt1 tt2
test 100 yingyu
test1 80 shuxue
test2 90 yuwen