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152
votes
4answers
27k views

/usr/bin vs /usr/local/bin on Linux

Why are there so many places to put a binary in Linux? There are atleast these five: /bin/ /sbin/ /usr/bin/ /usr/local/bin/ /usr/local/sbin/ And on my office box, I do not have write permissions ...
18
votes
5answers
27k views

Shell: How to read the bytes of a binary file and print as hexadecimal?

In shell, how can I read the bytes of a binary file I have, and print the output as hexadecimal numbers?
18
votes
5answers
2k views

Generating a random password; why isn't this portable?

I want to generate a random password, and am doing it like so: </dev/urandom tr -dc [:print:] | head -c 64 On my laptop, which runs Ubuntu, this produces only printable characters, as intended. ...
18
votes
3answers
22k views

How to find binary executables within a directory

How do I list all binary executable files recursively within a directory? I use find command like this: find /mydir/mysubdir -executable -type f All executable files are listed (excluding ...
13
votes
1answer
15k views

How to convert a shell script into a binary executable?

I want to convert my shell scripts into binary executable so that nobody else could edit or read it. Is there a way to convert it into a binary executable?
13
votes
1answer
5k views

Fix terminal after displaying a binary file

I'd tried command cat with an executable file: cat /bin/ls Now I can't read any word in this terminal (Linux console). How can I fix it?
13
votes
4answers
463 views

A shell-like environment for binary processing

This question came to me a couple of times before, now in response to the question Loop through binary data chunks from stdin in Bash Answers given in ...
11
votes
3answers
8k views

ASCII binary tools?

Which is a good tool to convert ASCII to binary, and binary to ASCII? I was hoping for something like: $ echo --binary "This is a binary message" 01010100 01101000 01101001 01110011 00100000 ...
11
votes
1answer
319 views

When can I edit strings in an executable binary?

I have an executable binary; let's call it a.out. I can see the binary contains strings $ strings a.out ... /usr/share/foo .... I need to change the string /usr/share/foo to /usr/share/bar. Can I ...
10
votes
3answers
17k views

convert a hex string to binary and send with netcat

I have a binary file that I can send with netcat: $ nc -l localhost 8181 < my.dat The file contains this: $ xxd my.dat 0000000: 0006 3030 3030 4e43 ..0000NC What I really ...
9
votes
5answers
16k views

Binary to hexadecimal and decimal in a shell script

I have a context where I need to convert binary to hexadecimal and decimal and viceversa in a shell script. Can someone suggest me a tool for this?
9
votes
1answer
9k views

Passing binary data to curl without using a @file

Is it possible to use curl and post binary data without passing in a file name? For example, you can post a form using binary via --data-binary: curl -X POST --data-binary @myfile.bin http://foo.com ...
8
votes
2answers
9k views

How can I handle raw binary data in a bash pipe?

I have a bash function that takes a file as a parameter, verifies the file exists, then writes anything coming off stdin to the file. The naive solution works fine for text, but I am having problems ...
8
votes
1answer
2k views

How to store an image file in bash variable?

After I use the following command, pngString="$(cat example.png)" echo -n "$pngString" > tmp.png I can't open the tmp.png as a PNG file. Maybe some information is lost when I use $pngString ...
8
votes
4answers
20k views

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? ...
8
votes
2answers
2k views

How could I use Bash to find 2 bytes in a binary file, increase their values, and replace?

I'm trying to find two bytes inside binary file, then increase value of those two bytes and replace them inside file. Those two bytes are on positions 0x82-0x83. For now on I have successfully ...
7
votes
2answers
631 views

Can hd and od replace each other?

hd and od are both dump viewers of binary content. Can hd be used wherever od is and vice versa?
7
votes
2answers
363 views

Is it possible to keep a FreeBSD system up to date (base system + packages) using only binaries?

I have been using Debian and NetBSD systems for a long time, and I have got used to do binaries upgrades for the base system and for packages (using pkgin with NetBSD) Now the NetBSD kernel does not ...
6
votes
2answers
778 views

What is produced after using cat on an image?

Let's say one creates a file like so: touch myFile You enter some text in it with vim or whatever, and then use cat myFile to spit the contents out into the terminal. Now, what happens when I use ...
6
votes
3answers
1k views

Mystery of binary files

This is about files straight from the compiler, say g++, and the -o (outfile) flag. If they are binary, shouldn't they just be a bunch of 0's and 1's? When you cat them, you get unintelligible ...
6
votes
2answers
344 views

In an empty environment, how are executables found?

For experimentation purposes I created a binary that prints the $PATH, and calls which as follows: #include <stdlib.h> #include <stdio.h> int main() { char *path = getenv("PATH"); ...
6
votes
1answer
3k views

How to follow (a la “tail -f”) a binary file from the beginning?

Is it possible to follow a binary file from the beginning, a la tail -f? This is useful in some cases, for example if I'm scping a file to a remote server, and at the same time I want to feed it to ...
6
votes
2answers
1k views

Can vim display ASCII characters only, and treat other bytes as binary data?

I already know vim -b, however, depending on the locale used, it displays multi-byte characters (like UTF-8) as single letters. How can I ask vim to only display ASCII printable characters, and ...
6
votes
1answer
395 views

Merge nonzero blocks of huge (sparse) file A into huge file B

I have two partial disk images from a failing hard drive. File B contains the bulk of the disk's contents, with gaps where sector reads failed. File A is the result of telling ddrescue to retry all ...
6
votes
1answer
3k views

Are there alternatives for `dd`?

What other tools should I use to read and write files with truncation, seeking and skipping. dd's command line options seem inconvenient and foreign and I don't like choosing between slow, but precise ...
5
votes
2answers
164 views

How to gather byte occurance statistics in binary file?

I'd like to know the equivalent of cat inputfile | sed 's/\(.\)/\1\n/g' | sort | uniq -c presented in ...
5
votes
2answers
3k views

tr complains of “Illegal byte sequence”

I'm brand new to UNIX and I am using Kirk McElhearn's "The Mac OS X Command Line" to teach myself some commands. I am attempting to use tr and grep so that I can search for text strings in a regular ...
5
votes
2answers
106 views

Get “Text Content” of Files

I was wondering if there is a tool to scrape text content of a file. Basically I would like to put in a pdf, word document, compressed file or anything else and get the text it contains out. There ...
5
votes
1answer
1k views

Loop through binary data chunks from stdin in Bash

I'm looking for something like while IFS= read -r -n $length str; do ... done but for binary data. Is it possible to do this using dd or other tools? Is there some technique to make these tools able ...
5
votes
1answer
97 views

Representing/quoting NUL on the command line

Can \0 be used on the command line? Background For testing corner cases in GNU Parallel I was curious whether all characters were correctly quoted on the command line. Most of them are: perl -e ...
5
votes
2answers
129 views

Is adding ./bin a bad idea

I can't think of any reason why adding ./bin to my PATH environment would be a very bad idea. I usually create bin folders in my projects that I am working in and I hate doing bin/command, it would ...
4
votes
4answers
4k views

Ubuntu vs. CentOS and Binary Compatibility

I am trying to install software that is built on CentOS 4.7. Do you know if it will also run in Ubuntu? I read CentOS is 100% binary compatible. Is the same true for the most recent version of Ubuntu? ...
4
votes
2answers
1k views

Is there a way to find files containing only non-printing characters?

I've got a program that's behaving badly and has created a number of files with only a few non-printing characters. If I were to cat the files, I see nothing (since they are non-printing chars). ...
4
votes
4answers
168 views

How can I convert two-valued text data to binary (bit-representation)

I have a text file with two (2) only possible characters (and maybe new lines \n). Example: ABBBAAAABBBBBABBABBBABBB (Size 24 bytes) How can I convert this to a binary file, meaning a bit ...
4
votes
3answers
7k views

Can xxd be used to output the binary representation of hex number , not a string?

I would like to generate a raw binary packet from hex in the command line for the purpose of testing a protocol. I'm hoping its simpler to do it this way than writing an aplication. Here is what ...
4
votes
1answer
230 views

how to run a software in linux without installing it

I am trying to run Rstudio download page link. On my Windows machine, I just downloaded the zip file from zip/tarballs section and was able to run .exe without installing anything on my machine. I'd ...
4
votes
2answers
1k views

Cannot execute binary in NixOS - No such file or directory

I tried to install the current oracle jre on a VM running NixOS. Now the following happens: [michas@cc:~]$ tar xvzf jre-7u40-linux-x64.tar.gz |grep bin/java jre1.7.0_40/bin/javaws ...
4
votes
3answers
145 views

Modifying binary during execution

I often come across the situation when developing, where I am running a binary file, say a.out in the background as it does some lengthy job. While it's doing that, I make changes to the C code which ...
4
votes
3answers
201 views

How to convert an unsigned decimal (less than 1<<32) to 4 bytes (binary) in bash?

Example: $ decimal=$(( RANDOM << 17 | RANDOM << 2 | RANDOM >> 13 )) $ echo $decimal $ printf "%08x" $decimal | xxd -r -p >bytes The result is in bytes file. Can it be done in ...
4
votes
2answers
931 views

Convert file with integers written in ascii to binary file of integers

I have a file that contains a long list of integers written in ascii separated with newlines, like such: -175 2 -19345 345592 -45 2355 etc... I want to convert this file into a "binary" file ...
4
votes
2answers
9k views

executing binary file: file not found

I know there are similar questions out there, but I haven't found a solution nor this exact case. The binary was built on Arch Linux using its GCC 4.7. The package works fine on the build system. The ...
4
votes
1answer
179 views

Linux from Binaries

I thought Linux from Scratch was a pretty cool tutorial, but I felt having to wait for everything to compile was a bit nerve-wreaking. Is there a tutorial similar to LFS except pre-compiled binaries ...
4
votes
2answers
181 views

Make ls distinguish scripts from binaries in output

Is it possible to make ls distinguish executable scripts from actual compiled binaries? The permissions are most often the same (+x), and with ls -F you get an asterisk suffix (*) for both, so it's ...
3
votes
3answers
917 views

Is it a script or is it a binary?

At the end, it looks like it's just a regular sh script: [USER@MACHINE ~/Desktop/D] head -2 truecrypt-7.1-setup-x86 #!/bin/sh CHECKSUM=163123652 but @the scripts end: [USER@MACHINE ~/Desktop/D] ...
3
votes
2answers
8k views

How to interpret an octal or hex dump of a binary file?

The binary file has strings and some numbers, If I do od -c filename or strings filename, I can see the strings properly. But, what about numbers? They are in some weird format. The text after doing ...
3
votes
2answers
93 views

Convert binary mode to text mode and the reverse option

By the following way I convert a simple binary file into a text file od –t x1 Check.tar | cut –c8- > Check.txt What is the opposite way to convert the Check.txt to Check.tar as the original file ...
3
votes
1answer
362 views

md5sum command binary and text mode

The GNU md5sum command has two modes: binary mode and text mode. I guess the difference is only on how newline characters are handled? Am I right? On GNU/Linux, the two modes always produce same ...
3
votes
4answers
338 views

Bash: For loop with binary range keeping control value binary

Let's say I have two bash variables that contain binary values: a=0011 # decimal 3 b=1000 # decimal 8 Is there a way I can loop through all the possible values between $a and $b keeping it binary? ...
3
votes
2answers
3k views

Why using cat on binary files messed up the terminal and how?

If I understand correctly the cat manual: concatenate files and print on the standard output cat will take files as argument and print them on standard output. What I don't get is if I use the ...
3
votes
2answers
2k views

how to find offset of one binary file inside another?

I have two binary files. One of few hundreds kilos and other of few gigabytes. I want to know whether the whole, smaller, file is contained within the larger one and if so then what is the offset from ...