# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\\/dev\\/sd[a-z][a-z]?(?<!\\/dev\\/sda)//g;t' <<< "/dev/sda
/dev/sdb
/dev/sdc
/dev/sdd
/dev/sde
/dev/sdaa
/dev/sdab
"
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