sed-delete-duplicate-consecutive-lines

#!/bin/sh
set -euf -o pipefail

##
# Delete duplicate, consecutive lines from a file (emulates "uniq").
#
# First line in a set of duplicate lines is kept, rest are deleted.
#
# From http://sed.sourceforge.net/sed1line.txt
#
#
# Contact: Joel Parker Henderson (joel@joelparkerhenderson.com)
# License: GPL
# Updated: 2015-01-25
##

sed '$!N; /^\(.*\)\n\1$/!P; D'