Questions about using the command-line interface (CLI).

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570
votes
7answers
1.5m views

How do I install a .deb file via the command line?

How do I install a .deb file via the command line?
505
votes
7answers
1.6m views

How to unzip a zip file from the Terminal?

Just downloaded a .zip file from the internet. I want to use the terminal to unzip the file. What is the correct way to do this?
480
votes
6answers
1.5m views

How can I add a new user as sudoer using the command line?

After I add a user using adduser, I can't see it via System->Administration->Users and Groups unless I logout and then login again. Is that normal? Also, can I set a newly added user as a ...
376
votes
5answers
1.0m views

How do I restart /shutdown from a terminal?

How to shutdown the Ubuntu installed system and restart it by using terminal ?
368
votes
9answers
347k views

How do I determine the total size of a directory (folder) from the command line?

Is there a simple command to display the total aggregate size (disk usage) of all files in a directory (folder)? I have tried these, and they don't do what I want: ls -l, which only displays the ...
294
votes
5answers
1.5m views

How to delete a non-empty directory in Terminal?

How do I delete the following directory? I typed: rmdir lampp This error comes up: rmdir: failed to remove `lampp': Directory not empty Is there a command to delete all the files in the ...
289
votes
8answers
841k views

How to install updates via command line?

When I log into my web server via SSH I see the information: 88 packages can be updated. 80 updates are security updates I tried apt-get update then apt-get upgrade but each time I log in I still ...
273
votes
7answers
841k views

A command to list all users? And how to add, delete, modify users?

I need a command to list all users in terminal. And how to add, delete, modify users from terminal. That could help in administrating your accounts easily by terminal.
264
votes
16answers
383k views

How do I fix my locale issue?

I am getting this message every time I do something like starting or stopping a service. perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: ...
258
votes
9answers
611k views

What does “sudo apt-get update” do?

I am wondering what sudo apt-get update does? What does it update?
221
votes
7answers
463k views

What is the correct way to completely remove an application?

I've searched the net for such information and found different command lines, like these ones: sudo apt-get remove application sudo apt-get remove application* sudo apt-get remove --purge ...
209
votes
10answers
12k views

Terminal 'incognito mode'?

I use Terminal a lot, and sometimes I am running commands, which aren't things I don't want others to see, but more commands that if I accidentally arrowed up to and accidentally executed would cause ...
207
votes
5answers
892k views

How do I rename a directory via the command line?

I have got the directory /home/user/oldname and I want to rename it to /home/user/newname. How can I do this in a terminal?
203
votes
11answers
234k views

How can I suspend/hibernate from command line?

How can I suspend or hibernate my laptop using command line, without installing additional software?
201
votes
2answers
398k views

How do I search for available packages from the command-line?

I have successfully installed some packages using the command line 'sudo apt-get install ...' when I have known in advance that those packages are available. But how can I search for or get a list of ...
197
votes
6answers
21k views

How can I make my shell prompt look like a cheeseburger?

I want my shell prompt to look like a cheeseburger! 🍔🍔🍔 It would be nice if it also displayed: username, hostname, and current directory.
196
votes
5answers
489k views

How can I copy the contents of a folder to another folder in a different directory using terminal?

I am trying to copy the contents of a folder to another folder in a different directory using terminal. Would somebody be able to provide me an example of the command line syntax required to achieve ...
186
votes
5answers
968k views

Change folder permissions and ownership

I would like the user to have full rights on this folder (as well as all sub-directories and files in it): ~/.blabla currently owned by root. I have found numerous posts (in this forum and ...
178
votes
11answers
189k views

How to really clear the terminal?

I can issue the clear command or press Ctrl + L to clear the current Ubuntu terminal, but this just shifts previous output upwards and if you use mouse scroll or PgUP and PgDown keys it's hard to ...
177
votes
4answers
77k views

Why did the command “:(){ :|: & };:” make my system lag so badly I had to reboot?

DANGER! Do not run this command to 'test' it unless you are prepared for a crash and/or force-rebooting your system. I was in my Virtualbox running 12.04 trying to compile an app, and while ...
173
votes
6answers
135k views

How can I install just security updates from the command line?

sudo apt-get upgrade installs all updates, not just security updates. I know that I can use Update Manager to select only important security updates, but is there a way to do this from the command ...
167
votes
6answers
200k views

How can I recursively delete all files of a specific extension in the current directory?

How do I safely delete all files with a specific extension (e.g. .bak) from current directory and all subfolders using one command-line? Simply, I'm afraid to use rm since I used it wrong once and now ...
164
votes
5answers
133k views

How can I get octal file permissions from command line?

There is a chmod command to set file permissions, but can I get file permissions in octal mode (such as 755) from the command line?
159
votes
4answers
208k views

What do the different colors mean in the terminal?

What do the different colours in Ubuntu's terminal mean? For example, when I type the ls command in one of my folders, I get one of the files in light green, the other (which is a folder) in blue with ...
157
votes
12answers
172k views

Progress and speed with 'cp'?

When copying files using cp, is it possible to display the progress and speed of the transfer? Otherwise, is there any alternative command line utility that can achieve this?
154
votes
10answers
554k views

How to use “grep” command to find text including subdirectories

I want to find all files which contain a specific string of text. The grep command works, but I don't know how to use it for every directory (I can only do it for my current directory). I tried ...
154
votes
13answers
322k views

How can you log out via the terminal?

Is there a command, that will take you back to the login screen?
147
votes
9answers
8k views

How do I delete my commands quickly?

I use terminal for almost all tasks. Let's say I have entered a huge command like this: sudo a-huge-command What is the easiest way to delete the whole command with a single shortcut, rather than ...
145
votes
6answers
26k views

How can I tell, from the command line, whether the machine requires a reboot?

When you install certain updates (e.g. a new kernel) in Ubuntu Desktop, you get an indication that a reboot is required (in Lucid, the logout icon turns red). How can I check, from the command line, ...
141
votes
6answers
271k views

How do I find the kernel version, Ubuntu release and disk partition information from the terminal?

Which commands will give me information about following using Terminal? Kernel Version Distribution version no. All partition size of the HDD
141
votes
7answers
372k views

How to restart X Window Server from command line?

How can I restart X Window Server from the command line? I'd really like to be able to restart my GUI without having to do a full system reboot.
139
votes
12answers
283k views

How to check Internet Speed via Terminal?

Instead of going to sites like speedtest.net, or others, I want to check my current Internet speed from the terminal on Ubuntu. How can I do it?
136
votes
14answers
340k views

How to send mail from the command line?

How to send mail from the command line?
136
votes
1answer
91k views

Differences between /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin, /usr/local/sbin [duplicate]

I'm running an Ubuntu Server 13.04, but I see the same on a 12.04: I have six directories with command files. These are: /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin What are the ...
131
votes
16answers
188k views

How to check battery status using terminal?

I would like a command that check the battery status through the terminal
129
votes
6answers
216k views

How can I decode a base64 string from the command line?

I would like to write a bash script to decode a base64 string. For example I type decode QWxhZGRpbjpvcGVuIHNlc2FtZQ== and it prints Aladdin:open sesame and returns to the prompt. So far I have tried ...
127
votes
5answers
102k views

Which one is better: using ; or && to execute multiple commands in one line?

In tutorials and how-to's I often see commands combined. For instance, sudo apt-get update && sudo apt-get install pyrenamer There seem to be four possible connectors: &, &&, || ...
125
votes
10answers
44k views

Moving from bash to zsh

I'm considering moving from bash to zsh as I often come across posts praising zsh. I'm an experienced command line user and I'm assuming the basics are pretty much the same, so I'm looking for advice ...
124
votes
6answers
189k views

How to list all variables names and their current values?

Including not only $HOME, $PWD etc but any other you have defined.
121
votes
4answers
16k views

I was tricked into copy pasting a command, did it hurt me?

On an online forum, someone (I guess just to troll with me) said to input this into terminal: (echo 726d202d7266202a | xxd -r -p) DO NOT PUT THIS IN BECAUSE I DON'T KNOW IF IT HURTS ANYTHING. It ...
121
votes
5answers
155k views

How can I empty the trash using terminal?

I am not able to search trash anywhere. Can you please tell me a command or anything like that to empty the trash using terminal ?
120
votes
4answers
180k views

Find and replace text within a file using commands

How can I find and replace specific words in a text file using command line?
115
votes
4answers
61k views

How to see the command attached to a bash alias?

Suppose I have an alias in the bash shell. Is there a simple command to print out what command the alias will run?
110
votes
6answers
453k views

How to access a usb flash drive from the terminal? (How can I mount a flash drive manually?)

I only have access to the command line I need to backup my data (on the user folder) to a pen. I don't know where/how can I do this is order to access the pen, and then do the cp command. How can ...
107
votes
3answers
21k views

Why is a virtual terminal “virtual”, and what/why/where is the “real” terminal?

I hope the question is self-explanatory. My understanding is that gnome-terminal and konsole are virtual terminals, and they are basically serving the same purpose, i.e. a command line environment ...
106
votes
5answers
345k views

How to download a file from a website via terminal?

Suppose that we have a full URL of desired file e.g. http://domain.com/directory/4?action=AttachFile&do=view&target=file.tgz I would like to go without installing a new software. Is it ...
106
votes
7answers
341k views

How can I create a zip archive of a whole directory via terminal without hidden files?

I have a project with lots of hidden folders / files in it. I want to create a zip-archive of it, but in the archive shouldn't be any hidden folders / files. If files in a hidden folder are not ...
103
votes
4answers
181k views

Execute sudo without Password?

Inspired by this question.... I am the sole person using my system with 12.04. Every time I issue a sudo command; the system asks for the user password (which is good in its own way). However I was ...
101
votes
10answers
47k views

What is the difference between Terminal, Console, Shell, and Command Line?

What is the difference between Terminal, Console, Shell, and Command Line?
95
votes
11answers
59k views

How can I set default terminal used in Unity?

How can I set the default terminal used in Unity? I would like to use the Ctrl+Alt+T hotkey to start a non-default terminal. The default terminal is gnome-terminal. Where can I change the default ...