共计 1189 个字符，预计需要花费 3 分钟才能阅读完成。
昨日举荐： 每天学一个 Linux 命令（32）：sort
命令简介
uniq 命令用于去除文件中反复行，个别与 sort 命令联合应用。
语法格局
uniq [选项] [规范输出 [ 输入]]
uniq [OPTION] [INPUT [OUTPUT]]
输出文件 #指定要去除的反复行文件。如果不指定该项，则从规范读入
输入文件 #指定要去除反复行后的内容要写入的输入文件。如果不指定此项，则将内容显示到规范输出设备（显示终端）。选项阐明
-c #在每列旁边显示该行反复呈现的次数
-d #只显示反复呈现的行与列
-f #疏忽比拟指定的字段
-s #疏忽比拟指定的字符
-i #不辨别大小写的比拟
-u #只显示呈现过一次的行与列
-w #指定要比拟的字符
-z #用 0 字节（NULL）代替换行符
--help #显示帮忙信息并退出
--version #显示版本信息并退出
利用举例
# 删除反复行
[root@centos7 ~]# cat test.txt
This is a test line
This is a test line
This is a test line
This is also a test line
This is also a test line
This is also also a test line
[root@centos7 ~]# uniq test.txt
This is a test line
This is also a test line
This is also also a test line
[root@centos7 ~]# sort test.txt | uniq
This is also also a test line
This is also a test line
This is a test line
#只显示繁多行
[root@centos7 ~]# uniq -u test.txt
This is also also a test line
[root@centos7 ~]# sort test.txt |uniq -u
This is also also a test line
#统计各行在文件中呈现的次数
[root@centos7 ~]# sort test.txt |uniq -c
1 This is also also a test line
2 This is also a test line
3 This is a test line
#在文件中找出反复的行
[root@centos7 ~]# sort test.txt |uniq -d
This is also a test line
This is a test line
每天学一个 Linux 命令（30）：cut
每天学一个 Linux 命令（31）：md5sum
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