# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/(?:https?:\\/\\/)?(?:www\.)?youtu\.?be(?:\.com)?\\/?.*(?:watch|embed)?(?:.*v=|v\\/|\\/)([\w\-_]+)\&?/$0\/modestbranding=1&rel=0/gm;t' <<< "http://www.youtube.com/watch?v=iwGFalTRHDA
http://www.youtube.com/watch?v=iwGFalTRHDA
http://youtu.be/embed/iwGFalTRHDA
http://youtu.be/n17B_uFF4cA
http://www.youtube.com/embed/iwGFalTRHDA
http://youtu.be/t-ZRX8984sc
https://www.youtube.com/embed/UIpuNuV23v0"
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