uniq Command | COMP2041 Week 1

What is uniq?什么是uniq？

The uniq command filters adjacent matching lines from input. Important: It only removes adjacent duplicates, so input should typically be sorted first. It's commonly used with sort to clean up data files.

uniq命令从输入中过滤相邻的匹配行。重要：它只删除相邻的重复项，所以输入通常应该先排序。它通常与sort一起使用来清理数据文件。

Basic Usage基本用法

$ sort file.txt | uniq
# Sort and remove duplicates
$ uniq -c file.txt
# Count occurrences of each line
$ uniq -d file.txt
# Show only duplicate lines
$ sort file.txt | uniq
# 排序并删除重复项
$ uniq -c file.txt
# 计算每行的出现次数
$ uniq -d file.txt
# 仅显示重复的行

Common Options常用选项

Option选项	Full Name完整名称	Description描述	Example示例
`-c`	count计数	Prefix with occurrence count加上出现次数前缀	`uniq -c items.txt`
`-d`	repeated重复	Show only duplicate lines仅显示重复的行	`uniq -d items.txt`
`-u`	unique唯一	Show only unique lines仅显示唯一的行	`uniq -u items.txt`
`-i`	ignore-case忽略大小写	Case-insensitive comparison不区分大小写比较	`uniq -i items.txt`
`-D`	all-repeated所有重复	Show all duplicate lines显示所有重复的行	`uniq -D items.txt`

Practical Scenarios实际场景

Count Item Frequency计算项目频率

$ sort access.log | uniq -c | sort -rn
# Count and show most common entries
$ sort access.log | uniq -c | sort -rn
# 计数并显示最常见的条目

Remove Duplicates删除重复项

$ sort -u file.txt > clean.txt
# Shortcut for sort | uniq
$ sort -u file.txt > clean.txt
# sort | uniq 的快捷方式

Memory Tricks记忆技巧

✨ "uniq" = unique - Make lines unique (remove adjacent duplicates)

✨ "uniq" = unique（唯一） - 使行唯一（删除相邻的重复项）

📊 -c = Count - Count how many times each line appears

📊 -c = Count（计数） - 计算每行出现多少次

👯 -d = Duplicates - Show only lines that are duplicated

👯 -d = Duplicates（重复） - 仅显示重复的行

⚠️ uniq requires sorted input! - Always sort first (or use sort -u)

⚠️ uniq需要排序的输入！ - 始终先排序（或使用sort -u）

uniq Commanduniq命令