I ran a Perl script on my system that created a bunch of files on my computer named as shown below. I could have typed rm -f A* but that could have deleted other files that have a capital “A” as the first letter of the filename. That is where wildcards come into play. I … Read more
This is how to change your login shell with the chsh command. This requires the user to log out and then back in to use their new shell. ubuntu ~ $ sudo chsh -s /bin/bashubuntu ~ $ sudo chsh -s /bin/bash Only a shell listed in /etc/shells may be used. But this is a very … Read more
Stripping comments out of a configuration file can be useful when submitting it to a forum for others to study. This is how to do this. ubuntu /etc/ssh $ grep -vE ‘^#’ sshd_configubuntu /etc/ssh $ grep -vE ‘^#’ sshd_config This will print the file to the terminal, allowing the user to copy the text with … Read more
This simple one-liner will print out all of the news headlines from the BBC news website in a simple text format. This is useful if you want to do something with a list like this. Or if you just want a listing to see if there is anything interesting happening. Updated command for 2017, as … Read more
Using the chmod command to change file permissions on a UNIX/Linux system. -rw-rw-r– 1 john john 203 09-02-12 07:16 pm out.out-rw-rw-r– 1 john john 203 09-02-12 07:16 pm out.out This file listing detail shows the information about the current file. The listing -rw-rw-r– shows the permissions for user, group and world. In this example, the … Read more
How to use noclobber with the tcsh shell on UNIX and Linux This example using the set noclobber command prevents existing files from being overwritten. 2:04am ubuntu /home/ubuntu ~> set noclobber2:04am ubuntu /home/ubuntu ~> set noclobber Now if I try to redirect to the file, this happens. 2:04am ubuntu /home/ubuntu ~> echo "" > chan.c … Read more
Useful Linux e-books and further reading for Linux users Guide to the Linux command line: http://www.securitronlinux.com/lc/Linux-Command-Line-Guide%20.png. Useful guide to the Linux command line for Linux newcomers. Guide to Linux permissions. How to set the permissions for Linux files with the command line: http://www.securitronlinux.com/lc/112_sysadmin_permissions.pdf. Debian Linux handbook. Useful information and tips for Linux newcomers: http://www.securitronlinux.com/lc/debian-handbook.pdf. Ubuntu … Read more
The title bars in the Gnome Shell desktop environment by default are much too thick. This simple code sample will make them thinner. Just create this file. ~/.config/gtk-3.0/gtk.css~/.config/gtk-3.0/gtk.css Then put this code into it. Updated for Gnome Shell on Ubuntu 18.04. # Gnome 3 – based on https://blog.samalik.com/make-your-gnome-title-bars-smaller/ .header-bar.default-decoration { padding-top: 1px; padding-bottom: 1px; font-size: … Read more
Install the tcsh shell on Ubuntu Linux easily with this simple guide The tcsh shell for Linux is a free but enhanced version of the old Berkeley UNIX C shell (csh). This is a very good alternative to the standard bash shell that most Linux machines come with. Download the tarball of the most recent … Read more
The /etc/passwd file on UNIX/Linux is where the user accounts for Linux are stored. This keeps your system safe as the passwords are stored as hashes in the /etc/shadow file, which is separate from the passwd file and is only accessible by the superuser. This keeps a system very safe. Red Hat Enterprise Linux uses … Read more
The Linux command-line offers many useful methods of creating many folders on your computer at once. This command will create a few folders on your system named one,two,three,four and create the folders five,six,seven,eight within each folder created. ~$ mkdir -p {one,two,three,four}/five/six/seven/eight~$ mkdir -p {one,two,three,four}/five/six/seven/eight This command will create four folders named one,two,three,four and put the … Read more
The BASH shell has many useful features that allow you to perform your tasks very easily. If you are running a program in a terminal and you wish to run another command whilst the first command is running, then press CTRL-Z to move the running process to the background. Then once you have finished the … Read more
To undo the cd command if you typed it by accident, enter this command. ~$ cd -~$ cd – This will take you back in the directory history. A very useful trick. Typing this is another good trick. ~$ cd –~$ cd — This seems to take the user back two steps. Another useful way … Read more
I have just installed the Windows 10 15025 build and the bash shell. I have to say that it works way better than earlier versions. The apt update and the apt upgrade commands worked straight away. And ping works now. The networking is greatly improved. This is a good asset to the Windows 10 desktop … Read more
Embedding the output of a command into a bash shell script is quite easy. Here is an example. echo "Hello $(whoami), the date is $(date -u). Have a nice day"echo "Hello $(whoami), the date is $(date -u). Have a nice day" This is the output this will give you. ┌─[jason@neo]─[~] └──╼ $echo "Hello $(whoami), the … Read more
The printerbanner command will create a dot matrix printer banner. Just run the command and then type a string and hit ENTER. jason@debian:~$ printerbanner Message: Debianjason@debian:~$ printerbanner Message: Debian Print out the contents of a text file in octal format. jason@debian:~$ od .dmrc 0000000 042133 071545 072153 070157 005135 060514 063556 060565 0000020 062547 062475 … Read more
The early Gnome desktop is quite interesting, it had a Windows styled menu with a easy to use taskbar. https://www.ocf.berkeley.edu/~bobk/gnome/1.2/gnome-1.2-menu02.png. Source: https://www.ocf.berkeley.edu/~bobk/gnome/. This is the old Gnome 1.0 configuration application. Very dated indeed, this is when they had Enlightenment as the Window Manager of Gnome. Although you could use Sawfish as well. http://www.linuxjournal.com/files/linuxjournal.com/linuxjournal/articles/031/3139/3139f1.jpg. The Gnome … Read more
A useful awk implementation to count the number of entries in the /etc/passwd file. john@deusexmachina:~$ sudo awk -F: ‘{ print $1 }’ /etc/passwd | wc -l 34john@deusexmachina:~$ sudo awk -F: ‘{ print $1 }’ /etc/passwd | wc -l 34 And the quintessential “Hello World” in Awk. john@deusexmachina:~$ awk ‘BEGIN { printf "%s, %s\n", "Hello", "World!" … Read more
To list all the files installed by a certain Debian package, use this command. dpkg -L [PACKAGENAME]. For example. ubuntu ~ $ dpkg -L vim /. /usr /usr/bin /usr/bin/vim.basic /usr/share /usr/share/lintian /usr/share/lintian/overrides /usr/share/lintian/overrides/vim /usr/share/bug /usr/share/bug/vim /usr/share/bug/vim/presubj /usr/share/bug/vim/script /usr/share/doc /usr/share/doc/vimubuntu ~ $ dpkg -L vim /. /usr /usr/bin /usr/bin/vim.basic /usr/share /usr/share/lintian /usr/share/lintian/overrides /usr/share/lintian/overrides/vim /usr/share/bug /usr/share/bug/vim /usr/share/bug/vim/presubj … Read more
The bash shell has some very useful features when using the command line. This can make using the command line much faster. For example, if you forget to type sudo before a command, this can be fixed this way. jason$ fdisk -l /dev/sda fdisk: cannot open /dev/sda: Permission deniedjason$ fdisk -l /dev/sda fdisk: cannot open … Read more