Category: Linux

First navigate to folder where you want to delete files, do’t use “ls”, “ls -la” as it can take lot of time before it will show result, so just make sure your in correct directory before running this command as it will delete all files in that directory

find . -type f -exec rm -v {} \;

Command will find all files one by one and will delete it.

If you want to delete only specific files for example only .jpg files

find . -maxdepth 1 -name "*.jpg" -print0 | xargs -0 rm

It will search files with .jpg extension in current directory and will delete it one by one.

Steghide is steganography tool to hide data in various kinds of image- and audio-files. first of all lets download RMP for centos

wget http://prdownloads.sourceforge.net/steghide/steghide-0.5.1-1.i386.rpm?download

after Download we can install it

rpm -ivh steghide-0.5.1-1.i386.rpm?download

if no error will be displayed then its ready but if error for example somthing like this

error: Failed dependencies:
ld-linux.so.2 is needed by steghide-0.5.1-1.i386
libc.so.6 is needed by steghide-0.5.1-1.i386
libc.so.6(GLIBC_2.0) is needed by steghide-0.5.1-1.i386
libc.so.6(GLIBC_2.1) is needed by steghide-0.5.1-1.i386
libc.so.6(GLIBC_2.1.3) is needed by steghide-0.5.1-1.i386
libc.so.6(GLIBC_2.2) is needed by steghide-0.5.1-1.i386
libgcc_s.so.1 is needed by steghide-0.5.1-1.i386
libgcc_s.so.1(GCC_3.0) is needed by steghide-0.5.1-1.i386
libjpeg.so.62 is needed by steghide-0.5.1-1.i386
libm.so.6 is needed by steghide-0.5.1-1.i386
libm.so.6(GLIBC_2.0) is needed by steghide-0.5.1-1.i386
libmcrypt.so.4 is needed by steghide-0.5.1-1.i386
libmhash.so.2 is needed by steghide-0.5.1-1.i386
libstdc++.so.5 is needed by steghide-0.5.1-1.i386
libstdc++.so.5(CXXABI_1.2) is needed by steghide-0.5.1-1.i386
libstdc++.so.5(GLIBCPP_3.2) is needed by steghide-0.5.1-1.i386
libstdc++.so.5(GLIBCPP_3.2.2) is needed by steghide-0.5.1-1.i386
libz.so.1 is needed by steghide-0.5.1-1.i386

Need to install all dependencies

yum install "compat-libstdc++-33.i686" "compat-libstdc++-33.x86_64";
yum install zlib-devel.i686;
yum install libjpeg-turbo-devel.i686;
rpm -ivh "http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm";
yum install libmcrypt-devel;
yum install mhash.i686;
yum install "libmcrypt.i686";

root@server [/tmp]# rpm -ivh steghide-0.5.1-1.i386.rpm?download
Preparing...                ########################################### [100%]
   1:steghide               ########################################### [100%]

now you can use it for example

steghide embed -cf in.jpg -ef out.jpg -p password

• in.jpg is file where we want to add hidden data
• out.jpg is ready file after add is completed
• password is pass to encrypt data

Optimization of PNG and JEPG images, using two different utilities first one is jpegoptim which is used to optimize JEPG images to use it recursively and optimize all of images in directory and sub directory you can use this command:

find . -name "*.jpg" | xargs jpegoptim --strip-all --all-progressive

This will strip all data and make images progressive.

PNG images can be optimized with Optipng

find . -name *.png | xargs optipng -nc -nb -o7 -full

For manipulation of binary data there are tons of tools on Linux but I will try to list some of great looking GUI tools

Bless Hex Editor

Written in mono/gtk it can be used in any platform where mono and gtk can work, this is feature which is listed on main website

Efficiently working with large files with fast data rendering on screen.
Supports multilevel redo/undo operations.
You can customizable data views use multiple tabs use find and replace operations.
Export of data to plain text and html or you can use plugins for different formats.

wxHex Editor

Newer soft then bless hex with some new features it’s written in C++ and can be used on mac and windows also.

For speeding up rendering and work on big files it’s not copying full file to ram so it’s good for really big files, memory usage is low, how there site is telling it’s using 25MB while working on several files with size more then 8GB.

Allows to work as low level disk editor you can edit sectors in hex, has X86 disassembly support, allows process memory editing and much more, last release was in 2014 and project is still beta.

DHEX

Running on Linux, HP-UX, FreeBSD, NetBSD, MacOS X, IRIX and Solaris, it has diff mode which means you can open two files same time and compare it, also have several different themes so you can customize layout. last release was in 2012.

GHex

Hex editor for gnome desktop nice looking with simple design, no so many function but you can still edit files and save hex as html, so nice looking gnome hex editor.