Linux see binary file

How to view a binary file?

From what I understand, a compiler makes a binary file that consists of 1’s and 0’s that a CPU can read. I have a binary file but how do I open it to see the 1’s and 0’s that are there? A text editor says it can’t open it. P.S. I have an assembly compiled binary that should be plain binary code of 1’s and 0’s?

no — OP specified «assembly compiled binary». That does not address the question. For instance, it’s not a music file, and it has structure. Without OP providing additional information, an unstructured tool is the place to start.

See my answer. And be warned that the term binary is used in two ways totally different in practice : «A binary file» means a file whose context is not pure ASCII-text. «A binary number» means a number written using its binary form.

You’re not going to get what you’re asking for. On a hard drive, the file is represented by magnetic changes. When the file is read, it’s turned into electrical pulses, which in turn are turned into binary by the processor. Binary itself is only a representation of a number as stated in the answers below. These numbers are then interpreted by the individual programs as the format expected by them, whether this is text or images or something different. You won’t see 1s and 0s by opening a binary file in nano.

11 Answers 11

unless you want to edit it of course. Most Linux distros have hexdump by default (but obviously not all).

Update

xxd does both binary and hexadecimal

For bin :

Various people have answered some aspects of the query, but not all.

All files on computers are stored as 1’s and 0’s. Images, text files, music, executable applications, object files, etc.

They are all 0’s and 1’s. The only difference is that they are interpreted differently depending upon what opens them.

When you view a text file using cat , the executable ( cat in this case) reads all the 1’s and 0’s and it presents them to you by converting them into characters from your relevant alphabet or language.

When you view a file using an image viewer, it takes all the 1’s and 0’s and turns them into an image, depending on the format of the file and some logic to work it all out.

Compiled binary files are no different, they are stored as 1’s and 0’s.

arzyfex’s answer gives you the tools to view those files in different ways, but reading a file as binary works for any file on a computer, as does viewing it as octal, or hex, or indeed ASCII, it just might not make sense in each of those formats.

If you want to understand what an executable binary file does, you need to view it in a way which shows you the assembler language (as a start), which you can do using,

which is a disassembler, it takes the binary content and converts it back into assembler (which is a very low level programming language). objdump is not always installed by default, so may need to be installed depending on your Linux environment.

NB: as @Wildcard points out, it’s important to note the files don’t contain the characters 1 and 0 (as you see them on the screen), they contain actual numeric data, individual bits of information which are either on (1) or off (0). Even that description is only an approximation of the truth. They key point is that if you do find a viewer which shows you the 1’s and 0’s, even that is still interpreting the data from the file and then showing you the ASCII characters for 0 and 1. The data is stored in a binary format (see the Binary number link above). Pierre-Olivier’s community wiki entry covers this in more detail.

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binary file linux

Binaries are files that contain compiled source code (or machine code). Binary files are the files which contain compiled source code (or machine code). They are also called executable files because they can be executed on the computer. Binary directory contains following directories: /bin.

How do I view a binary file in Linux?

1. $ file /bin/ls. .
2. $ ldd /bin/ls. .
3. $ ltrace ls. .
4. $ hexdump -C /bin/ls | head. .
5. $ readelf -h /bin/ls. .
6. $ objdump -d /bin/ls | head. .
7. $ strace -f /bin/ls. .
8. $ cat hello.c.

How do you write a binary file?

1. address of data to be written in the disk.
2. size of data to be written in the disk.
3. number of such type of data.
4. pointer to the file where you want to write.

How do I view a binary file?

1. Go to menu Edit > Find.
2. In the Find What box, select a previous search string from the drop-down list or type the data you want to find.
3. Select any of the Find options and choose Find Next.

Is PDF a binary file?

PDF files are either 8-bit binary files or 7-bit ASCII text files (using ASCII-85 encoding). Every line in a PDF can contain up to 255 characters.

What is a binary file and how do I open it?

Opening a binary file is very easy. For example, use any hex editor to open the file and view its contents in multiple formats such as hexadecimal and Ascii. Use Google to find a free hex editor for your operating system. Many programmer’s editors have this feature built in or as an optional plugin.

How do I run a binary executable in Linux?

To make the file executable first, right-click on the binary file and then properties and go to permissions. On Permissions thick the checkbox with the option allows executing the file as program close the program and double click on the binary.

How do you convert binary to words?

To convert binary numbers to letters, just grab a piece of paper and a pen or pencil and add up the binary values of all the 1s. Then look up your total number as an ASCII decimal in the chart above.

Where are binary commands stored?

Purpose. Utilities used for system administration (and other root-only commands) are stored in /sbin , /usr/sbin , and /usr/local/sbin . /sbin contains binaries essential for booting, restoring, recovering, and/or repairing the system in addition to the binaries in /bin .

Is .exe a binary file?

EXE files are different from BAT files since they contain executable binary data rather than plain text commands. They are stored in the Portable Executable (PE) format. The EXE file format includes various headers and sections that tell Windows how to run a program.

Is .dat a binary file?

BIN File : The BIN file type is primarily associated with ‘Binary File’. . DAT File : The DAT file type is primarily associated with ‘Data’. Can be just about anything: text, graphic, or general binary data. Data file in special format or ASCII.

What is a binary file used for?

A binary file is a file whose content must be interpreted by a program or a hardware processor that understands in advance exactly how it is formatted. That is, the file is not in any externally identifiable format so that any program that wanted to could look for certain data at a certain place within the file.

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How to use bash script to read binary file content?

I want to read a character and then a fixed length of string (the string is not null terminated in the file, and its length is given by the preceding character). How can I do this in a bash script? How to define the string variable so that I can do some post-processing on it?

5 Answers 5

If you want to stick with shell utilities, you can use head to extract a number of bytes, and od to convert a byte into a number.

export LC_ALL=C # make sure we aren't in a multibyte locale n=$(head -c 1 | od -An -t u1) string=$(head -c $n) 

However, this does not work for binary data. There are two problems:

Command substitution $(…) strips final newlines in the command output. There’s a fairly easy workaround: make sure the output ends in a character other than a newline, then strip that one character.

string=$(head -c $n; echo .); string=$

If you have binary data, you’ll want to switch to a language like Perl or Python.

If you want to be able to deal with binary file in shell, the best option (only?) is to work with hexdump tool.

hexdump -v -e '/1 "%u\n"' binary.file | while read c; do echo $c done 

head -cX binary.file | hexdump -v -e '/1 "%u\n"' | while read c; do echo $c done 

Read length (and work with 0 as length) and then «string» as byte decimal value:

len=$(head -c1 binary.file | hexdump -v -e '/1 "%u\n"') if [ $len -gt 0 ]; then tail -c+2 binary.file | head -c$len | hexdump -v -e '/1 "%u\n"' | while read c; do echo $c done fi 

Rather than just present a bunch of commands, can you explain what they do and how they work? What do the options mean? What output can the user expect from your commands? Please do not respond in comments; edit your answer to make it clearer and more complete.

Well, I can copy manpages here, but I don’t see the point. There is only basic commands used here, the only trick is the usage of hexdump.

read -N stops at null bytes, so this is not a suitable way to work with binary data. In general, shells other than zsh can’t cope with nulls.

UPDATE (with hindsight). This question/answer (my answer) makes me think of the dog which keeps chasing the car.. One day, finally, he catches up to the car.. Okay, he caught it, but he really can’t do much with it. This anser ‘catches’ the strings, but then you can’t do much with them, if they have embedded null-bytes. (so a big +1 to Gilles answer.. another language may be in order here.)

dd reads any and all data. It certainly won’t baulk at zero as a «length». but if you have \x00 anywhere in your data, you will need to be creative how you handle it; dd has no propblems with it, but your shell script will have problems (but it depends on what you want to do with the data). The following basically outputs each «data string», to a file with a line divider between each strin.

btw: You say «character», and I assume you mean «byte».
but the word «character» has become ambiguous in these days of UNICODE, where only the 7-bit ASCII character-set uses a single byte per character. And even within the Unicode system, byte counts vary depending on the method of encoding characters, eg. UTF-8, UTF-16, etc.

Here is a simple script to highlight the difference between a Text «character» and bytes.

STRING="௵" echo "CHAR count is: $" echo "BYTE count is: $(echo -n $STRING|wc -c)" # CHAR count is: 1 # BYTE count is: 3 # UTF-8 ecnoded (on my system) 

If your length character is 1-byte long and indicates a byte-length, then this script should do the trick, even if the data contains Unicode characters. dd only sees bytes regardless of any locale setting.

This script uses dd to read the binary file and outputs the strings seperated by a «=== =================================»; echo $div ((skip=0)) # read bytes at this offset while ( true ) ; do # Get the «length» byte ((count=1)) # count of bytes to read dd if=binfile bs=1 skip=$skip count=$count of=datalen 2>/dev/null (( $( strlen=$((0x$(/dev/null ddgetct=$( echo -e «\n$div» >>dataline # add a newline for TEST PURPOSES ONLY. cat dataline # ((skip=skip+count)) # read bytes from and including this offset done # echo

This script builds test data which includes a 3-byte prefix per line.
The prefix is a single UTF-8 encoded Unicode character.

# build test data # =============== prefix="௵" # prefix all non-zero length strings will this obvious 3-byte marker. prelen=$(echo -n $prefix|wc -c) printf \\0 > binfile # force 1st string to be zero-length (to check zero-length logic) ( lmax=3 # line max . the last on is set to 255-length (to check max-length logic) for ((i=1;i<=$lmax;i++)) ; do # add prefixed random length lines suflen=$(numrandom /0..$((255-prelen))/) # random length string (min of 3 bytes) ((i==lmax)) && ((suflen=255-prelen)) # make last line full length (255) strlen=$((prelen+suflen)) printf \\$((($strlen/64)*100+$strlen%64/8*10+$strlen%8))"$prefix" for ((j=0;j>binfile # 

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