File sh.rellink of Package texlive

set +o posix
relpath ()
{
    local state=$- ; set +x
    local OLDIFS IFS
    local -a orgwords
    local -a locwords
    local -i relp=0
    local -i deep=0
    local p l
    local path=""

    OLDIFS="$IFS"; IFS=/
    eval orgwords=(${1// /\\\\ }) ; shift
    eval locwords=(${1// /\\\\ }) ; shift
    IFS="$OLDIFS"
    unset OLDIFS

    deep=0
    relp=0
    for l in "${locwords[@]}" ; do
        if test "$l" = ".." ; then
	    ((deep++))
	    continue
	elif test $deep -gt 0 ; then
	    while ((deep-- > 0)) ; do
		unset locwords[$((relp+deep))]
		(((relp-1)-deep < 0)) || unset locwords[$(((relp-1)-deep))]
	    done
	    continue
        fi
	((relp++))
    done
    locwords=(${locwords[@]})

    deep=0
    relp=0
    for p in "${orgwords[@]}" ; do
	if test "$p" = ".." ; then
	    ((deep++))
	    continue
	elif test $deep -gt 0 ; then
	    while ((deep-- > 0)) ; do
		unset orgwords[$((relp+deep))]
		(((relp-1)-deep < 0)) || unset orgwords[$(((relp-1)-deep))]
	    done
	    continue
	fi
	((relp++))
    done
    orgwords=(${orgwords[@]})

    deep=0
    relp=0
    for p in "${orgwords[@]}" ; do
	eval l="\${locwords[$((deep++))]}"
	if test "$l" != "$p" -o $relp -ne 0 ; then
	    ((relp++))
	    path="${path}/$p"
	    test -n "$l" || continue
		if test $relp -eq 1 ; then
		    path="..${path}"
		else
		    path="../${path}"
		fi
	 fi
    done
    unset orgwords p l

    if test $deep -lt ${#locwords[@]} ; then
	relp=0
	while test $relp -lt $deep; do
	    unset locwords[$((relp++))]
	done
	while test ${#locwords[@]} -gt 0  ; do
	    path="../${path}"
	    unset locwords[$((relp++))]
	done
    fi

    echo "$path"
    [[ $state =~ x ]] && set -x
}

rellink ()
{
    local state=$- ; set +x
    local relpath=$(relpath "${1%/*}" "${2%/*}" 2>/dev/null)
    if test -d "$1" ; then
	ln -sf "$relpath/${1##*/}/" "$2"
    else
	ln -sf "$relpath/${1##*/}"  "$2"
    fi
    [[ $state =~ x ]] && set -x
}