Preview script to check if file is binary

[zongou]

Lf assumes that a file containing '\U+0000' is a binary file.
in shell script. we can not do the same directly with grep,
But we can print file in hex then check if there are 0000.
Im using lf on android also, there is no hexdump provided by toybox, but there is base64.

By running

printf '\0' | base64
printf '\0\0'  | base64

We can know that the pattern that NUL character base64 encoded is 'AA'.
So we can check if a file is binary in this way

if base64 "$1" | grep -q AA; then
  echo "Assume Binary file"
else
  echo "Assume textual file"
fi