Delimiters in SED substitute command @ % | ; :
The follwing two commands are same.
sed 's@/home/@/myhome@g' saple.txt
sed 's/\/home\//\/myhome\//g' saple.txt
The part of an input line on which the Regular Expression matches is represented by & ,
and It can be used in the replacement part.
sed 's/input/&output/g' output: inputoutput
Grouping can be used in sed like normal regular expression.
A group is opened with “\(” and closed with “\)”.
sed 's@\(myhome\).*@\1@g'
Parenthesize first character of each word
echo "Welcome To The Geek Stuff" | sed 's/\(\b[A-Z]\)/\(\1\)/g'
Source and More Info
