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2488 votes
24 answers

How to list all installed packages

I'd like to output a list of all installed packages into a text file so that I can review it and bulk-install on another system. How would I do this?
  • 54.7k
2020 votes
9 answers

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?
  • 20.5k
1558 votes
26 answers

How can PPAs be removed?

I've added many PPAs using the add-apt-repository command. Is there a simple way to remove these PPAs? I've checked in /etc/apt/sources.list for the appropriate deb lines but they aren't there. This ...
1425 votes
27 answers

"The following packages have been kept back:" Why and how do I solve it?

I just added a PPA repository for the development version of the GIMP, but I get this error: $ apt-get update && apt-get upgrade ... The following packages have been kept back: gimp gimp-...
  • 20.4k
1345 votes
11 answers

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

How do I install a .deb file via the command line?
  • 25.3k
1291 votes
10 answers

How do I save terminal output to a file?

How do I save the output of a command to a file? Is there a way without using any software? I would like to know how.
  • 13.2k
1221 votes
8 answers

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 ...
  • 12.4k
1156 votes
25 answers

Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?

I get this error when trying to use apt-get: E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is ...
1090 votes
13 answers

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 ...
1082 votes
15 answers

Where is the cron / crontab log?

I want to verify that my cron job is executing and at what time. I believe there is a log for my sudo crontab -e jobs, but where? I searched google and found recommendations to look in /var/log (...
1077 votes
5 answers

How can I use docker without sudo?

On Docker's documentation pages, all example commands are shown without sudo, like this one: docker ps On Ubuntu, the binary is called It also does not work without sudo: sudo ...
  • 38.3k
1056 votes
8 answers

What command do I need to unzip/extract a .tar.gz file?

I received a huge .tar.gz file from a client that contains about 800 mb of image files (when uncompressed.) Our hosting company's ftp is seriously slow, so extracting all the files locally and sending ...
  • 14.8k
1042 votes
16 answers

How can I update my nodeJS to the latest version?

I have installed nodeJS on Ubuntu with following code sudo apt-get install nodejs Since I am a new user for ubuntu I also ran this code too sudo apt-get install npm Now when I type nodejs --...
1033 votes
9 answers

Is there a command to list all users? Also to add, delete, modify users, in the terminal?

I need a command to list all users as well as commands to add, delete and modify users from terminal - any commands that could help in administrating user accounts easily by terminal.
1028 votes
7 answers

How to upgrade a single package using apt-get?

How do I update a single package? As far as man apt-get says apt-get upgrade doesn't take a package/list of packages as parameter: upgrade upgrade is used to install the newest versions of all ...
  • 11.1k
973 votes
15 answers

How to get bash or ssh into a running container in background mode?

I want to ssh or bash into a running docker container. Please, see example: $ sudo docker run -d webserver webserver is clean image from ubuntu:14.04 $ sudo docker ps CONTAINER ID IMAGE ...
947 votes
12 answers

How do I uncompress a tarball that uses .xz?

I'm used to extracting tarballs with a -xfz flag, which handles gzip and bzip2 archives. Recently I've run into a .tar.xz file and I would like to uncompress it in one step using tar, how can I do ...
  • 69.6k
934 votes
14 answers

How to keep processes running after ending ssh session?

Let's say I launch a bunch of processes from a ssh session. Is it possible to terminate the ssh session while keeping those processes running on the remote machine?
933 votes
5 answers

How do I shut down or reboot from a terminal?

How can I shut down or reboot Ubuntu using terminal commands?
  • 97.9k
929 votes
7 answers

How can I add a user as a new 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 log out and then log in again. Is that normal? Also, can I set a newly added user as a sudoer ...
  • 10.6k
927 votes
20 answers

Error message "sudo: unable to resolve host (none)"

When I run sudo the terminal is stuck for a few seconds and then outputs an error message. My terminal looks like this: ubuntu@(none):~$ sudo true sudo: unable to resolve host (none) What can I do ...
  • 10.7k
926 votes
17 answers

How to add a directory to the PATH?

How do I add a directory to the $PATH in Ubuntu and make the changes permanent?
  • 10.5k
919 votes
9 answers

How to enable or disable services?

I read about how to enable and disable services in Ubuntu and it seems that there are different possibilities to manage them. The first method I found is update-rc.d to add new services to startup, ...
  • 32.4k
881 votes
8 answers

Find and replace text within a file using commands

How can I find and replace specific words in a text file using command line?
  • 10.8k
871 votes
5 answers

How to extract files to another directory using 'tar' command?

I thought tar archive.tar /users/mylocation would work, but it doesn't. How can I do that?
  • 8,813
854 votes
9 answers

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 ...
  • 8,694
830 votes
8 answers

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 ...
  • 8,303
819 votes
9 answers

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 packagename' when I have known in advance that those packages are available. But how can I search for or get a ...
  • 8,295
815 votes
21 answers

How do you monitor the progress of dd?

dd is a wonder. It lets you duplicate a hard drive to another, completely zero a hard drive, etc. But once you launch a dd command, there's nothing to tell you of its progress. It just sits there at ...
  • 16.4k
806 votes
8 answers

How to add existing user to an existing group?

I want to add the Apache user (www-data) to the audio group. I've read the man page for useradd, but I'm not having any luck. I'm running xubuntu 11.10. Here's what I'm doing: $ sudo useradd -G audio ...
  • 11.8k
790 votes
22 answers

Command for determining my public IP?

If I check with google, I can see my public IP. Is there something on the Ubuntu command-line which will yield me the same answer?
  • 8,369
781 votes
16 answers

How do I reset a lost administrative password?

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there. I've tried the suggestions on the ...
user avatar
776 votes
9 answers

How to increment a variable in bash?

I have tried to increment a numeric variable using both var=$var+1 and var=($var+1) without success. The variable is a number, though bash appears to be reading it as a string. Bash version 4.2.45(1)...
  • 7,771
774 votes
4 answers

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 directory ...
  • 7,967
771 votes
4 answers

What is the difference between apt and apt-get?

I read about the new fancy progress bar which was added to apt 1.0 in Softpedia and how to enable it here. However on running sudo apt-get update, I did not see the fancy progress bars. On reading the ...
  • 12.1k
754 votes
39 answers

How do I remove old kernel versions to clean up the boot menu?

Every time I install a new Linux kernel, it gets left in the grub_config, making the boot menu longer each time. I know I can manually search through the installed packages and remove them. Does ...
750 votes
7 answers

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?
  • 17.4k
737 votes
18 answers

How do I find the amount of free space on my hard drive?

Is there a way to quickly check the amount of free / used disk space in Ubuntu? I would assume you could right click on 'file system' in the file browser and choose 'properties' or something but ...
  • 9,823
727 votes
82 answers

What Application Indicators are available?

This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions ...
724 votes
47 answers

What should I do when Ubuntu freezes?

All operating systems freeze sometimes, and Ubuntu is no exception. What should I do to regain control when... just one program stops responding? nothing at all responds to mouse clicks or key ...
  • 74.4k
724 votes
9 answers

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 ...
  • 13.2k
718 votes
10 answers

How to run scripts on start up?

How can I run scripts automatically when Ubuntu starts up so I don't have to run them manually after startup?
  • 32.5k
715 votes
22 answers

How can I extract a page range / a part of a PDF?

Do you have any idea how to extract a part of a PDF document and save it as PDF? On OS X it is absolutely trivial by using Preview. I tried PDF editor and other programs but to no avail. I would like ...
  • 7,159
712 votes
9 answers

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 ...
  • 7,553
689 votes
24 answers

How can I reduce the file size of a scanned PDF file?

I have a 72.9MB PDF file that I need to shrink into under 500KB. The file was a JPEG image that I had scanned, and then converted to pdf.
  • 7,029
689 votes
10 answers

How do I find the package that provides a file?

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a ...
  • 9,521
687 votes
21 answers

How do I get the CPU temperature?

How do I get the CPU temperature?
  • 10.9k
687 votes
9 answers

What does "sudo apt-get update" do?

I am wondering what sudo apt-get update does? What does it update?
  • 10.8k
686 votes
16 answers

How to check Internet Speed via Terminal?

Instead of going to sites like, I want to check my current Internet speed from the terminal on Ubuntu. How can I do it?
  • 11.2k
649 votes
14 answers

How do I resolve unmet dependencies after adding a PPA?

Occasionally, when I'm installing stuff, I get an error like the following: Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the ...
  • 59.2k

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