# SED - Stream Editor
# Delete lines from input files
# Options: -i = modify original file or write to new file ( > output.txt)
# Delete range of lines from 5 to end of file, write output to output file
sed '5, $d' input.txt > output.txt
# Delete line 5 only
sed '5d' input.txt
# Delete lines 7,12 and 16
sed '7d;12d;16d' input.txt
# Delete all lines except specified range
sed '1,3d; 7,$d' input.txt
# Delete empty lines in place
sed -i '/^$/d' input.txt
# Delete lines matching a pattern (case sensitive)
sed '/<pattern>/d' input.txt
# Make pattern case insensitive
sed '/<pattern>/I d' input.txt
# Delete line NOT matching a patterns
sed '/<pattern>/!d' input.txt