show-special-characters-in-unix-while-using-less-command
To see what that character is:
less -r sourcefile
or
od -c sourceFile
for a more verbose view.
unix-linux-sed-ascii-control-codes-nonprintable
To sed out the offending control code:
sed 's/'`echo "\033"`'/ /g'
where \033 is replaced with whatever is actually there.
