How to check if the file is a binary file and read all the files which are not?

Question

How can I know if a file is a binary file?

For example, compiled c file.

I want to read all files from some directory, but I want ignore binary files.

Answer 1

BSD grep

Here is a simple solution to check for a single file using BSD grep (on macOS/Unix):

grep -q "\x00" file && echo Binary || echo Text

which basically checks if file consist NUL character.

Using this method, to read all non-binary files recursively using find utility you can do:

find . -type f -exec sh -c 'grep -q "\x00" {} || cat {}' ";"

Or even simpler using just grep:

grep -rv "\x00" .

For just current folder, use:

grep -v "\x00" *

Unfortunately the above examples won't work for GNU grep, however there is a workaround.

GNU grep

Since GNU grep is ignoring NULL characters, it's possible to check for other non-ASCII characters like:

$ grep -P "[^\x00-\x7F]" file && echo Binary || echo Text

^{Note: It won't work for files containing only NULL characters.}