CODEWITHSUNDEEP
linuxbashshellperl
user3161924
user3161924

Reputation: 2273

How can a shell script determine if a file is binary or text?

Have a situation where I need a shell or bash script to determine if a file is binary or not. The issue here is that the linux environment does not have file available and the grep version is from busybox which doesn't support -I. I found a perl method (the perl version is old supports -e but not -E) of it working but it's slow. Does anyone have a faster method of determining if a file is binary? TIA!!

#!/bin/sh

is_text_file() { 
  # grep -qI '.' "$1"   ### busy box grep doesn't support
  perl -e 'exit((-B $ARGV[0])?1:0);' "$1"  ### works but is slow
}

do_test_text_file_on_dir() {
  for f in "$1"/*; do
    [ -f "$f" ] || continue
    if is_text_file "$f"; then
      echo "$f" is not a binary file
    fi
  done
}

do_test_text_file_on_dir ~/testdir

Upvotes: 2

Views: 624

Answers (1)

ikegami
ikegami

Reputation: 385647

Avoid the time it takes to repeatedly load perl by doing all the work in Perl.

#!/usr/bin/perl

for (@ARGV) {
   stat($_)
      or warn("Can't stat \"$_\": $!\n"), next;

   -f _ && !-B _
      or next;

   print("\"$_\" isn't a binary file\n");
}

Usage:

do_test_text_file_on_dir ~/testdir/*

Note: !-B _ is equivalent to -T _ except for empty files.

Upvotes: 3

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