SED

sed 's/day/night/g' old >new

sed 's/[a-z]*/(&)/' old >new

replace \n

sed -e :a -e '$!N;s/\n/ /;ta' old >new

replace \n

sed -e :a -e '$b;N;s/\n/ /;ba' old >new

selectively select line to replace

sed '/^SPECIAL_TEXT/s/to_be_replaced/replace_by/g' old >new

show only changed ones

sed -n 's/to_be_replaced/replace_by/p' old >new

show only changed ones conditionally

sed -n 's/\b[Nn]andan\b/NANDAN/p' old >new

echo Today is 15 Feb 2010 | sed 's/[0-9]\{1,2\} \+[A-Za-z][a-z]\+/*&*/' o\p: Today is *15 Feb* 2010

delete nth line

sed 'nd' 2.txt > 2.int

delete 1st line

sed -i -e 1d 2.txt

delete last line

sed '$d' f.txt

delete all empty lines

sed '/^$/d' f.txt

sed '/./!d' f.txt

delete between lines m and n

sed 'm,nd' f.txt

delete all lines having word name

sed '/name/d' f.txt

replace

`echo $i| sed "s/.mpeg.txt$//"`.txt

change columns into line

sed -e :a -e '$!N;s/\n/ /;ta' file1 > file 2