# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/<img.*src="(.*\)/<img src="http:\/\/multimedia.pol.dk\/archive\/00802\/SNOOTS.jpg"/i;t' <<< "<img style=\"gdgdF\" src=\"http://multimedia.pol.dk/archive/00802/RB_PLUS_Danskerne___802815p.jpg\" width=\"369\" height=\"253\" alt=\"SPRITKONTROL\" />"
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