Basic Replace Syntax:

• sed -i 's/KENNY/LENNY/g' filename

• Substitute all occurrences of "KENNY" with "LENNY"

Delete Line Containing String:

• sed -i '/SEINFELD/d' filename

Delete Empty Lines:

• sed -i '/^$/d' filename

Delete First Line:

• sed '1d' filename

sed '1,2d' filename → delete the first two lines

sed 's/\t/ /g' filename → replace tabs with spaces

sed -n '12,18p' filename → print only lines 12 to 18

sed '12,18d' filename → delete lines 12 to 18

sed G filename → insert an empty line after every line

sed '8!s/seinfeld/S/' filename → replace "seinfeld" with "S" on every line except line 8