# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\s*<div class="new">.*?href="((?:.*?)channel=(.*?))".*?src="(.*?)".*?<\/a>\s*<\/div>/HREF: \1\nCHANNEL: \2\nSRC: \3\n\n/gms;t' <<< "<div class=\"new\"> <a class=\"block\" target=\"_blank\" href=\"http://somesite:8080/hls/mango1.m3u8?token=34523sedfsdfsdf&e=123456789&channel=mango1\" data-toggle=\"modal\" data-target=\"#mango1\">
<div class=\"image-container\"> <img src=\"images/mango1.png\" class=\"img-responsive\" > </div>
</a> </div>
<div class=\"new\"> <a class=\"block\" target=\"_blank\" href=\"http://somesite:8080/hls/mango2.m3u8?token=sfaesfraesgh452342&e=987654321&channel=mango2\" data-toggle=\"modal\" data-target=\"#mango2\">
<div class=\"image-container\"> <img src=\"images/mango2.png\" class=\"img-responsive\" > </div>
</a> </div>"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html