#! /bin/sh 

# Carlos Duarte <cgd@mail.teleweb.pt>, 980722/990607 
# diff between d, and D sed commands

for i in d D; do 
	case $i in 
	d) echo "running with command 'd' (no output)" ;;
	D) echo "running with command 'D' (only 2nd line)" ;;
	esac
	cat<<EOF|
line 1
line 2
EOF
	sed -e 1!q -e N -e $i 
done

# 
# d: delete pattern space and goto end 
# D: delete up to first newline and goto start 
# 
# i.e. neither d or D produce output, but 'd' will fetch
# a new line, and continue from start, while 'D' branches
# directly to top
#