To check if a file contains any special (non “standard” ascii) characters, use Perl and POSIX character classes. Depending on how permissive you want to be use one of:
-
allow only whitespace and standard ascii print characters (i.e.
[\x20-\x7E])$ perl -nwe 'print if /[^[:space:][:print:]]/' file.txt -
also allow control characters (i.e.
[\x00-\x7F])$ perl -nwe 'print if /[^[:ascii:]]/' file.txt
This recipe has been packed as a script on github: gremlins.
