sed, a stream editor.

Replace word with words from file:

sed -i 's|word|words' file

Replace multiple target (sperate with ;):

sed -i 's|word|words;s|hello|bye' file

Delete lines contain import:

sed -i '/import/d' file

Delete lines contain import and the next line:

sed -i '/import/,+1d' file

Delete specify line by line number [(cite:>bash tool to get nth line from a file)]

sed -i "${NUM}q;d" file

• https://www.gnu.org/software/sed/manual/sed.html
• http://www.grymoire.com/Unix/Sed.html
• https://www.digitalocean.com/community/tutorials/the-basics-of-using-the-sed-stream-editor-to-manipulate-text-in-linux