# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\/[^\/]*(?=\/[^\/]*$)//gm;t' <<< "https://fbcdn-creative-a.akamaihd.net/hads-ak-xaf1/t45.1600-4/s110x80/10156615_6017073002888_1171145694_n.png"
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