The wall command is a perfect way to send a message to all logged on users on a Linux machine. This is used when you shutdown to alert all users that the system will be shutting down. The example below shows me sending the output of the ps command to all users. ubuntu@ip-172-31-20-234:~$ sudo ps … Read more
The steghide program is used to embed one image inside another. I will be showing you how to embed a text file inside an image and then set a passphrase to use when recovering the text file. This is a simple example, I am embedding the file my.txt into a screenshot from a movie. root@user:~# … Read more
Window manager themes. RISC styled WM theme for Xfce4: http://www.marutan.net/themes.php. GTK themes. Mac OS Classic theme for Xfce4: http://xfce-look.org/content/show.php?content=144719. Mac OS classic GTK2 theme: http://gnome-look.org/content/show.php/Mac+OS+9+Platinum+gtk+theme?content=110444. Plane GTK: http://gnome-look.org/content/show.php/Plane-Gtk3.6?content=156309. Classic 95 Windows `95 theme for MATE and Gnome: http://gnome-look.org/content/show.php/Classic95?content=157298. How to create a look-alike Windows XP desktop using IceWM: http://kmandla.wordpress.com/projects/lookalike-windows-xp-classic/. Windows 3.1 theme for Xfce4: http://xfce-look.org/content/show.php/Redmond3+%28Windows+3.1+theme%29?content=121526. … Read more
To reboot your Linux machine, use the sudo reboot command. Another way is to type sudo shutdown -r now. This command will also shut down your machine. ┌─[jason@darkstar]─[~] └──╼ $sudo init 0┌─[jason@darkstar]─[~] └──╼ $sudo init 0 Use this command to reboot your computer. ┌─[jason@darkstar]─[~] └──╼ $sudo init 6┌─[jason@darkstar]─[~] └──╼ $sudo init 6 To lookup the … Read more
This command will display a count of successful logins to your Linux machine. jason-H55-USB3% grep ‘session opened’ /var/log/auth.log | wc -l 67jason-H55-USB3% grep ‘session opened’ /var/log/auth.log | wc -l 67 This will display a count of failed login attempts to your Linux machine. jason-H55-USB3% grep ‘FAILED LOGIN’ /var/log/auth.log | wc -l 3jason-H55-USB3% grep ‘FAILED LOGIN’ … Read more
The Linux command line is very useful for finding files, the find command is the best way to locate files on your filesystem. This is a simple example. knoppix@Microknoppix:~$ sudo find /proc -name "meminfo" /proc/meminfoknoppix@Microknoppix:~$ sudo find /proc -name "meminfo" /proc/meminfo Use the -maxdepth parameter to only search a certain number of levels deep into … Read more
If you click a link in Google and the forum post you wanted to read requires a login to view, click back and then click the green drop down arrow at the end of the link, then click the cached option. This will open a cached version of the forum posting. This way, you can … Read more
Get your uptime with the uptime command on Linux. Last login: Tue Oct 28 13:55:23 on ttys000 iMac05:~ admin$ uptime 11:24 up 111 days, 20:38, 2 users, load averages: 0.35 0.16 0.14Last login: Tue Oct 28 13:55:23 on ttys000 iMac05:~ admin$ uptime 11:24 up 111 days, 20:38, 2 users, load averages: 0.35 0.16 0.14 The … Read more
The lsdvb command will list all installed DVB hardware in your Linux system. Here it is showing my Realtek DVB stick. You need to use sudo to enable this command to gather more information. jason-H55-USB3 [lsdvb] ~/Documents jason-H55-USB3% sudo lsdvb lsdvb: Simple utility to list PCI/PCIe DVB devices Version: 0.0.4 Copyright (C) Manu Abraham … Read more
The emerge -atv emacs command will tell you what packages will be merged when installing a copy of Emacs on your Gentoo GNU/Linux system. ec2-user@ip-172-31-30-35 ~ $ sudo emerge -atv emacs * IMPORTANT: 8 news items need reading for repository ‘gentoo’. * Use eselect news to read news items. These are the … Read more
To remove a package in Ubuntu, use the sudo apt-get remove command. This will uninstall the package. jason-H55-USB3 [mc] ~ 14-10-18 8:47PM jason-H55-USB3% sudo apt-get remove linphone Reading package lists… Done Building dependency tree Reading state information… Done The following packages were automatically installed and are no longer required: libexosip2-10 liblinphone5 libmediastreamer-base3 libortp9 libosip2-10 libupnp6 … Read more
The route command on Linux will show the kernel routing table, this is very useful as in my case, when you are using a VPN and you need to see the routing table. This is an example, I am viewing the routing table on my Ubuntu 14.04 machine running OpenVPN. jason-H55-USB3 [route -v] ~ 14-10-17 … Read more
Using the shellshock bash bug on an iMac. iMac04:~ admin$ env VAR1=’me() {echo "hello"}\ ‘ /bin/echo "hello" helloiMac04:~ admin$ env VAR1=’me() {echo "hello"}\ ‘ /bin/echo "hello" hello Getting free hard disk space easily. iMac04:~ admin$ df -Hla Filesystem Size Used Avail Capacity iused ifree %iused Mounted on /dev/disk0s2 89G 64G 25G 73% 15757422 6089307 72% … Read more
The iperf utility is used to transfer data from one machine to another over the Internet. This is a client-server utility and is the go-to utility to test a Wide Area Network connection. To use this, type sudo apt-get install iperf. Then open port 5001 in your router and/or firewall to allow the incoming connection … Read more
This is a variant of the shellshock bug for bash that still works on a patched system. I am using Ubuntu 14.04 and this still works for me. env VAR1=’me() {echo "hello"}\ ‘ /bin/touch /home/$LOGNAME/my.textenv VAR1=’me() {echo "hello"}\ ‘ /bin/touch /home/$LOGNAME/my.text So you can still put arbitrary content after the function definition in a bash … Read more
The shellshock bug for Linux is a wake up call for all Linux administrators and home users, but this is not the end of the world. The Linux distribution developers will issue patches very soon after a leak of a bug like this. There is not going to be a massive catastrophe that the media … Read more
A vulnerable cygwin shell. Using the shellshock vulnerability to run ls in cygwin. Homer@bejiitas ~ $ x='() { :;}; `/bin/ls -hula`’ bash -c : bash: total 53K drwxrwxr-x+ 1 Homer Homer 0 Sep 26 18:38 . drwxrwxrwt+ 1 Homer Homer 0 Sep 26 2013 .. -rw-rw—- 1 Homer Homer 222 Sep 26 2013 .bash_history -rwxrwxr-x … Read more
This is how to copy files from the local machine to your Amazon instance when you are logged into the EC2 instance via SSH. Firstly, connect to the remote AWS instance by SSH. Then use the sftp command to connect back to your local Linux machine. sftp -P 443 [email protected] -P 443 [email protected] Then, you … Read more
This guide, [openvpn.net] has a good guide to setting up an OpenVPN server on a Linux machine. I used this guide as the other guides online are not as good and often do not lead to a satisfactory result. I am using one on Linux and I can connect to it on my Windows machine … Read more
Use this command to find all files in a directory that are larger than 1 megabyte. find . -maxdepth 1 -type f -size +1M -exec ls -Shal {} \+ | headfind . -maxdepth 1 -type f -size +1M -exec ls -Shal {} \+ | head Here is this command in practice. This is a very … Read more