#sed command options delete some lines
- based on line numbers sed -i -e '1d' passwd
- string based delete sed -i -e '/nologin/ d' passwd
add some lines
- sed -i -e '1 a Hello' -e '/monogd/ a Hello World' passwd modify(change) some lines sed -i -e '2 c Hello Universe' -e '/centos/ c Hello Galaxy' passwd
delete some words sed -i -e 's|Hello||g' passwd modify(substitute) some words sed -i -e 's|bin|BIN|g' passwd sed -i -e '10s|bin|BIN|g' passwd Instead of | we can use / , ?, :, ;, #, @