Bug 12216

Summary:	sort: unique deletes to much/wrong lines
Product:	Busybox	Reporter:	4yg_4mm6p8ifiten
Component:	Other	Assignee:	unassigned
Status:	NEW ---
Severity:	normal	CC:	busybox-cvs
Priority:	P5
Version:	1.31.x
Target Milestone:	---
Hardware:	Other
OS:	Linux
Host:		Target:
Build:

Description 4yg_4mm6p8ifiten 2019-09-16 20:27:21 UTC

a line is missing:

echo -e "1a\n1b\n2a" | sort -un
1a
2a


as expected:

echo -e "1a\n1b\n2a" | sort -u | sort -n
1a
1b
2a

Comment 1 Ron Yorston 2020-01-25 12:30:09 UTC

I don't think this is a bug.

Firstly, coreutils 'sort' exhibits the same behaviour.

Secondly, the man page for POSIX 'sort' says that the '-u' option will "suppress all but one in each set of lines having equal keys" and that the '-n' option will "restrict the sort key to an initial numeric string". When these options are combined only the numeric part of the line is used to determine lines are unique.