Grep : How to grep for strings inside binary data

Tags : grep binary text string

Grep or Global Regular Expression Print is a very useful Unix/Linux command that I've practically used everyday. So, recently a co-worker asked me how to grep for a piece of string inside binary data files ?

for example, there is a binary file

printf "\x01 text \x00\r\ntext\r\n\x02text text\r\n\x92" > data.bin

What he wanted is to grep for the 'text' string for the data.bin file

To do that, use the cat command with -v flag

From the cat man page:

-v Display non-printing characters so they are visible. Control characters print as ^X' for control-X; the delete character (octal 0177) prints as `^?.

Non-ASCII characters (with the high bit set) are printed as `M-' (for meta) followed by the character for the low 7 bits.

without the -v flag, the grep result will look something like this

cat data.bin | grep text

Binary file (standard input) matches

therefore, use cat -v before passing the result to grep

cat -v data.bin | grep text

^A text ^@^M


^Btext text^M

Hope this short tutorial on greping for strings inside binary data file can be useful to you.

Tags : grep binary text string

By Adam Ng

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.