Linux命令之uniq

学习笔记：<linux shell编程>书籍

命令：uniq

语法：sort [arg] [File]

功能：文本去重

参数：

Usage: uniq [OPTION]... [INPUT [OUTPUT]]

Discard all but one of successive identical lines from INPUT (or

standard input), writing to OUTPUT (or standard output).

Mandatory arguments to long options are mandatory for short options too.

-c, --count prefix lines by the number of occurrences

-d, --repeated only print duplicate lines

-D, --all-repeated[=delimit-method] print all duplicate lines

delimit-method={none(default),prepend,separate}

Delimiting is done with blank lines.

-f, --skip-fields=N avoid comparing the first N fields

-i, --ignore-case ignore differences in case when comparing

-s, --skip-chars=N avoid comparing the first N characters

-u, --unique only print unique lines

-z, --zero-terminated end lines with 0 byte, not newline

-w, --check-chars=N compare no more than N characters in lines

--help display this help and exit

--version output version information and exit

实例1. 去除重复项

test@node-h:~/Jeff> cat fruits_2.txt

apples

apples

peaches

pears

bananas

cherries

cherries

解释：显示fruits_2.txt文本

test@node-h:~/Jeff> uniq fruits_2.txt

apples

peaches

pears

bananas

cherries

解释：不加任何参数，去除fruits_2.txt的重复行。

实例2. 去除重复项，并显示重复的次数

test@node-h:~/Jeff> sort fruits_2.txt | uniq -c

2 apples

1 bananas

2 cherries

1 peaches

1 pears

解释：参数-c 显示重复的次数

实例3. 去除重复项，并仅显示重复行

test@node-h:~/Jeff> sort fruits_2.txt | uniq -d

apples

cherries

解释：-d 仅仅显示重复行

实例3. 去除重复项，并显示不重复行

test@node-h:~/Jeff> sort fruits_2.txt | uniq -u

bananas

peaches

Pears

解释：-u 显示不重复行