#!/bin/bash

function drop_first ()
{
    local line
    # skip
    read line;
    # proxy
    while read line; do
    echo $line;
    done;
}

function join ()
{
    local delimeter="$1"
    sed -e "s/^/${delimeter}\n/g" | drop_first | xargs
}

echo "1a 1b
2a 2b 2c
3a" | drop_first | join "delim"

# result: '2a 2b 2c delim 3a'