#!/bin/bash
LASTFILE=""

for MATCHES in $(grep -i -R "head -[ 0-9]" ./* | cut -f1 -d:) ; do
        if [ ! "${MATCHES}" = "${LASTFILE}" ] ; then
                mv ${MATCHES} ${MATCHES}.orig
                sed -e 's/head -\(.*\)/head -n \1/' \
                < ${MATCHES}.orig \
                > ${MATCHES}
                rm ${MATCHES}.orig
        fi
        LASTFILE="${MATCHES}"
done

for MATCHES in $(grep -i -R "tail -[ 0-9]" ./* | cut -f1 -d:) ; do
        if [ ! "${MATCHES}" = "${LASTFILE}" ] ; then
                mv ${MATCHES} ${MATCHES}.orig
                sed -e 's/tail \([-+]\)\(.*\)/tail -n \1\2/' \
                < ${MATCHES}.orig \
                > ${MATCHES}
                rm ${MATCHES}.orig
        fi
        LASTFILE="${MATCHES}"
done