uniq命令

 uniq - 显示或移除重复的行(report or omit repeated lines)

格式(synopsis):

uniq [OPTION]... [INPUT [OUTPUT]]

说明(description):

uniq 命令读取由[INPUT]参数指定的标准输入或文件.该命令首先比较相邻的行，然后除去第二行和该行的后续副本。重复的行一定相邻。

命令参数长选项和对应的短选项

-c|--count        ##在行首显示该行重复的次数
-d|--repeated     ##仅显示重复的行
-f|--skip-fields  ##忽略比较指定的栏
-i|--ignore-case  ##不区分大小写
-s|--skip-chars   ##忽略比较指定的字符位
-u|--unique       ##仅显示出现一次的行
-w|--check-chars  ##指定每行要比较的前几个字符
--help            ##显示帮助信息
--version         ##显示版本信息

示例(examples):

# cat >test <<EOF
This is the first user.
This is the first user.
THis is the first user.
This IS xhe first user.
tHIS IS the first user.
This is the first user.
THIS IS THE FIRST USER.
EOF
# uniq test  ##删除重复的行
This is the first user.
THis is the first user.
This IS xhe first user.
tHIS IS the first user.
This is the first user.
THIS IS THE FIRST USER.
# uniq -c test  ##在行首显示该行重复的次数
      2 This is the first user.
      1 THis is the first user.
      1 This IS xhe first user.
      1 tHIS IS the first user.
      1 This is the first user.
      1 THIS IS THE FIRST USER.
# uniq -i -c test ##不区分大小写，计算每行重复的次数
      3 This is the first user.
      1 This IS xhe first user.
      3 tHIS IS the first user.
# uniq -s 2 -c test ##比较第二个字符，计算每行重复的次数
      3 This is the first user.
      1 This IS xhe first user.
      1 tHIS IS the first user.
      1 This is the first user.
      1 THIS IS THE FIRST USER.
# uniq -f 3 test  ##不比较第三栏
This is the first user.
THIS IS THE FIRST USER.
# uniq -d test  ##显示重复的行
This is the first user.
# uniq -u test  ##显示只出现一次的行
THis is the first user.
This IS xhe first user.
tHIS IS the first user.
This is the first user.
THIS IS THE FIRST USER.
# uniq -w 11 test  ##删除重复的行，每行最多只比较前11个字符
This is the first user.
THis is the first user.
This IS xhe first user.
tHIS IS the first user.
This is the first user.
THIS IS THE FIRST USER.