I am running Ubuntu 14.04 on my machine. I am feeling lost when I see different command line commands (or what exactly are they called?) like sudo, apt-get, mkdir, -R, -n etc. while installing different software like Node JS, Mongo DB etc.

What are some good resources where I can find what do different Linux/Unix commands exactly mean?

closed as too broad by slm Oct 24 '14 at 18:09

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  • Command line utilities almost always have "man(ual) pages" which you can view with man, e.g., man apt-get. TLDP has lots of guides, how-tos, etc. If you click through "Guides" and scroll down, there's an "Introduction to Linux" and "GNU/Linux Command-Line Tools Summary". – goldilocks Oct 24 '14 at 17:58

man pages are your friend. Whenever you see a command you've never used, run man [name of command]

For example, man sudo will tell you:

NAME sudo, sudoedit - execute a command as another user

and, lower down:

DESCRIPTION sudo allows a permitted user to execute a command as the superuser or another user, as specified in the sudoers file. The real and effective uid and gid are set to match those of the target user as specified in the passwd file and the group vector is initialized based on the group file (unless the -P option was specified). If the invoking user is root or if the target user is the same as the invoking user, no password is required. Otherwise, sudo requires that users authenticate themselves with a password by default (NOTE: in the default configuration this is the user's password, not the root password). Once a user has been authenticated, a time stamp is updated and the user may then use sudo without a password for a short period of time (5 minutes unless overridden in sudoers).

If the wording is too complicated, that's when you do a Google search such as "Linux what does sudo do?"

  • sudo stands for substitute user do
  • mkdir stands for make directory
  • apt stands for advanced packaging tool

The options like -r or -f are just random letters, but sometimes stands for real stuff.

Like -u in ytdl stands for update, you can also run it using --update or -h which can also be run using --help

Use man to get information about them.

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