Insert lines into certain files. After first and before last line

insertine

#!/bin/bash
# insert text lines after first line and before last line of file
# $1 = a glob expression like */assets/*.css
# $2 = a literal to be inserted after first line
# $3 = same as above but inserted before last line
for f in $1; do
	eval "sed -ri '1 s/(.*)/\1\n$2; $ s/(.*)/$3\n\1/' \"$f\""
done