100 Useful Command-Line Utilities
by Oliver; 201497. apt-get, brew, yum
From An Introduction to the Command-Line (on Unix-like systems) - Installing Programs on the Command Line: In the course of this article, we've made passing references to programs like htop, pstree, nginx, and tmux. Perhaps you have these on your computer but, if not, how do you get them? You can usually go to a program's webpage, download the source code, and build it on your computer (google the mantra ./configure; make; make install). However, you'll probably discover that your system has some crucial deficiency. Something's out of date, plus the program you're trying to install requires all these other programs which you don't have. You've entered what I call dependency hell, which has a way of sending you to obscure corners of the internet to scour chat rooms for mysterious lore.When possible, avoid this approach and instead use a package manager, which takes care of installing a program—and all of its dependencies—for you. Which package manager you use depends on which operating system you're running. For Macintosh, it's impossible to live without brew, whose homepage calls it, "The missing package manager for OS X." For Linux, it depends on your distribution's lineage: Ubuntu has apt-get; Fedora has yum; and so on. All of these package managers can search for packages—i.e., see what's out there—as well as install them.
Let's use the program gpg2 (The GNU Privacy Guard), a famous data encryption tool which implements the OpenPGP standard, to see what this process looks like. First, let's search:
$ brew search gpg2 # Mac $ yum search gpg2 # Fedora $ apt-cache search gpg2 # UbuntuInstalling it might look like this:
$ brew install gpg2 # Mac $ sudo yum install gnupg2.x86_64 # Fedora $ sudo apt-get install gpgv2 # UbuntuThe exact details may vary on your computer but, in any case, now you're ready to wax dangerous and do some Snowden-style hacking! (He reportedly used this tool.)
