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uniq

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  1. uniq

uniq

uniq removes consecutive duplicate lines from sorted input, so it's almost always used after sort in a pipeline. -c prefixes each line with a count of how many times it occurred. Without sorting first, uniq will miss duplicates that aren't adjacent.

Warning: uniq only removes *adjacent* duplicate lines — always sort first if duplicates might not be next to each other.

Example: uniq

bash 
#!/bin/bash
printf "apple\nbanana\napple\napple\ncherry\n" | sort | uniq
echo "---"
printf "apple\nbanana\napple\napple\ncherry\n" | sort | uniq -c
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