I'd use file and pipe the output into grep or awk to find text files, then extract just the filename portion of file's output and pipe that into xargs.
something like:
file * | awk -F: '/ASCII text/ {print $1}' | xargs -d'\n' -r flip -u
Note that the grep searches for 'ASCII text' rather than any just 'text' - you probably don't want to mess with Rich Text documents or unicode text files etc.
You can also use find (or whatever) to generate a list of files to examine with file:
find /path/to/files -type f -exec file {} + | \
awk -F: '/ASCII text/ {print $1}' | xargs -d'\n' -r flip -u
The -d'\n' argument to xargs makes xargs treat each input line as a separate argument, thus catering for filenames with spaces and other problematic characters. i.e. it's an alternative to xargs -0 when the input source doesn't or can't generate NULL-separated output (such as find's -print0 option). According to the changelog, xargs got the -d/--delimiter option in Sep 2005 so should be in any non-ancient linux distro (I wasn't sure, which is why I checked - I just vaguely remembered it was a "recent" addition).
Note that a linefeed is a valid character in filenames, so this will break if any filenames have linefeeds in them. For typical unix users, this is pathologically insane, but isn't unheard of if the files originated on Mac or Windows machines.
Also note that file is not perfect. It's very good at detecting the type of data in a file but can occasionally get confused.
I have used numerous variations of this method many times in the past with success.
Best Answer
You might try the
fileutility. According to the manpage:You might have to play around with the regular expression but something like:
file has lots of options, so you might want to take a closer look at the man page. I used the first option I found that seemed to output easily-to-grep output.