# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/’s\/\_[0-9]{14}_\/\_\/’
/_/gm;t' <<< "10.209.85.14_20160831010034_show_run.txt
10.209.85.17_20160831010057_show_run.txt
10.209.85.18_20160831010104_show_run.txt
10.209.85.19_20160831010112_show_run.txt
10.209.85.20_20160831010001_show_run.txt
10.209.85.226_20160831010224_show_run.txt
10.209.85.227_20160831010228_show_run.txt
10.209.85.228_20160831010303_show_run.txt
10.217.76.10_20160831010159_show_run.txt
10.217.76.11_20160831010159_show_run.txt
10.217.76.12_20160831010206_show_run.txt
10.217.76.13_20160831010212_show_run.txt
10.217.76.14_20160831010219_show_run.txt
10.217.76.7_20160831010119_show_run.txt
10.217.76.9_20160831010122_show_run.txt
10.217.77.226_20160831010309_show_run.txt
10.217.77.227_20160831010342_show_run.txt
10.217.77.228_20160831010417_show_run.txt
"
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