Terminal commands

Question

I have some questions about some Terminal commands:

Why must you do sudo apt-get update before installing an program or after downloading something? Does it update Ubuntu then?
What is the different between sudo gedit /location/to/afile.txt and gksu gedit /location/to/afile.txt?
Why people don't use -y on the end of a command, like for example in sudo apt-get install programx -y.
What does the -i and -l (are there any more) mean in a Terminal?
How can I unpack any .zip or .tar.gz file in a Terminal?

3. It is a good idea to check whether apt is doing what it should or something utterly stupid (its very good at that) 4. depends on the program - run COMMAND --help, COMMAND -h or man COMMAND to find what those options do for that command 5. http://askubuntu.com/questions/262068/how-to-extract-a-tar-gz-file and http://askubuntu.com/questions/86849/how-to-unzip-a-zip-file-from-the-terminal — Wilf, Jun 02 '14 at 08:19
Shouldn't this question be split into 5 different questions? It's rather unlikely that others will have this exact set of questions, but separately they're all quite common. — waldyrious, Jun 02 '14 at 14:31
These are separate questions and each can be answered: some have already been answered. — Warren Hill, Jun 02 '14 at 17:28

kraxor · Accepted Answer · 2014-06-02T08:21:54.967

sudo apt-get update updates the repository information of apt, so you can install the latest version of packages.

sudo gedit will ask you for a password in the terminal window, while gksu gedit prompts for a password with a GUI.

Most people like to review any changes they make with root permissions, that's why they refrain from using sudo apt-get -y and similar.

As for -i and -l, these look like parameters you would give to a command. Each command behaves differently and uses different switches, so without knowing the specific command, it's not possible to tell what these mean. Read the manual (man apt-get, for example) or try using --help with any command.

Use unzip file.zip to extract a zip file and tar xzf file.tar.gz to extract a tar.gz file.

score 3 · Answer 2 · edited Apr 13 '17 at 12:24

Why must you do sudo apt-get update before installing an program or after downloading something? Does it update Ubuntu then?

No , it won't update Ubuntu. It just update the repositories and PPA's.

What is the different between sudo gedit /location/to/afile.txt and gksu gedit /location/to/afile.txt?

Don't open gui application as root through sudo instead of sudo, you have to use gksu. gksu package is not installed by default, so run this command sudo apt-get install gksu to install gksu package.

Why don't people not use -y on the end of a command, like sudo apt-get programx -y?

Because people want apt-get to always propmt(ask for permission) before installing packages.

How can I unpack any .zip or .tar.gz file by Terminal?

unzip filename.zip
tar -xzvf file.tar.gz

Terminal commands

2 Answers2