#Bash 的 uniq 命令
uniq [OPTION]... [INPUT [OUTPUT]]
功能
过滤文件中连续的重复行。
类型
可执行文件（/usr/bin/uniq），属于 coreutils。
参数
OPTION选项：-c,--count- 按出现的次数给行添加前缀-d,--repeated- 仅打印重复的行一次-D- 打印所有重复行--all-repeated[=METHOD]- 打印所有重复行，并使用空行分隔分组：none- 不使用空行分隔分组；同-D（默认）prepend- 每组之前空行separate- 两组之间空行
-f,--skip-fields=N- 避免比较前N个字段--group[=METHOD]- 打印所有行，并使用空行分组separate- 两组之间空行prepend- 每组之前空行append- 每组之后空行both- 每组前后空行
-i,--ignore-case- 忽略大小写-s,--skip-chars=N- 不比较行的前N个字符-u,--unique- 仅打印唯一的行-z,--zero-terminated- 以空字符（\0）作为行的结尾，而不是换行符（\n）-w,--check-chars=N- 只比较行的前N个字符--help- 显示帮助--version- 显示版本
INPUT- 输入文件；如果没有这个参数或指定为-，则从标准输入读取OUTPUT- 输出文件；如果没有这个参数或指定为-，则打印到标准输出
#示例
$ cat 1.txt
Primers 编程伙伴
Primers 编程伙伴
https://xplanc.org/primers/
https://xplanc.org/primers/
Primers 编程伙伴
Primers 编程伙伴
https://xplanc.org/primers/
https://xplanc.org/primers/
Primers 编程伙伴 https://xplanc.org/primers/
$ uniq 1.txt # 过滤连续的重复行
Primers 编程伙伴
https://xplanc.org/primers/
Primers 编程伙伴
https://xplanc.org/primers/
Primers 编程伙伴 https://xplanc.org/primers/
$ uniq -c 1.txt # 打印重复次数
2 Primers 编程伙伴
2 https://xplanc.org/primers/
2 Primers 编程伙伴
2 https://xplanc.org/primers/
1 Primers 编程伙伴 https://xplanc.org/primers/
$ uniq -d 1.txt # 仅打印连续的重复行一次
Primers 编程伙伴
https://xplanc.org/primers/
Primers 编程伙伴
https://xplanc.org/primers/
$ uniq -D 1.txt # 仅打印所有重复行
Primers 编程伙伴
Primers 编程伙伴
https://xplanc.org/primers/
https://xplanc.org/primers/
Primers 编程伙伴
Primers 编程伙伴
https://xplanc.org/primers/
https://xplanc.org/primers/
$ uniq -u 1.txt # 仅打印唯一行
Primers 编程伙伴 https://xplanc.org/primers/
#推荐阅读
#手册
UNIQ(1) User Commands UNIQ(1)
NAME
uniq - report or omit repeated lines
SYNOPSIS
uniq [OPTION]... [INPUT [OUTPUT]]
DESCRIPTION
Filter adjacent matching lines from INPUT (or standard input), writing
to OUTPUT (or standard output).
With no options, matching lines are merged to the first occurrence.
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, one for each group
-D print all duplicate lines
--all-repeated[=METHOD]
like -D, but allow separating groups with an empty line;
METHOD={none(default),prepend,separate}
-f, --skip-fields=N
avoid comparing the first N fields
--group[=METHOD]
show all items, separating groups with an empty line;
METHOD={separate(default),prepend,append,both}
-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
line delimiter is NUL, 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
A field is a run of blanks (usually spaces and/or TABs), then non-blank
characters. Fields are skipped before chars.
Note: 'uniq' does not detect repeated lines unless they are adjacent.
You may want to sort the input first, or use 'sort -u' without 'uniq'.
AUTHOR
Written by Richard M. Stallman and David MacKenzie.
REPORTING BUGS
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
COPYRIGHT
Copyright © 2023 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
comm(1), join(1), sort(1)
Full documentation <https://www.gnu.org/software/coreutils/uniq>
or available locally via: info '(coreutils) uniq invocation'
GNU coreutils 9.4 April 2024 UNIQ(1)