LINUX OPERATION

  LINUX APPLICATION

The software packages are somewhere in the online repositoies, APT handles a local database on the user's hard drive that contains information's about the available packages and where they are located. So when the types the command, apt-get install conky, the APT will start finding the package named conky in the database and will install conky once user types 'y' (yes). To get the all newly uploaded packages on the repositories, user need to update APT regularly.

To update APT database:

apt-get update

To update the APT database and also upgrade the security updates and patches that might be available for some installed softwares, users may do it at once just by using the commands like this: apt-get update; apt-get upgrade

And remember all of the package management tools I am discussing, will need user to be in root or superuser, for example to install software in debian based distributions you will use apt-get followed by sudo then It will ask you to enter password.

sudo apt-get install conky

sudo apt-get remove conky

sudo apt-get update

Insert password to install any package

yum: For RPM based Linux distributions, like, Fedora, Red HatYou will not have any trouble understanding yum because its same as apt-get. As 'apt-get' installs software packages for Debian packages, like that 'yum' installs software packages for RPM packages. It can also like apt-get download and install packages from a repository.

  Yum install ${packagename}

To remove software packages, just use remove

yum remove ${packagename}

There is one thing to note that yum does not keep a local database by default in user's hard disk. So there is no need to update it. But to install available security paches and bug fixes, use the following command:

yum update

If user wants to update any single package then do it in the following way:

yum update ${packagename}

Tar Balls

  You would remember in Windows you've Zip files .zip or in Mac .sit. The same way here in Linux you have Tar Balls (files) ending with extentions, like, .tar, .tar.gz, .tgz, or something else. To unpack a tar ball (file), use the following command:

tar -xzvf ${filename}.tar.gz

The parameters are x to extract files, z to filter through gzip for decompression (leave this off if the file does not have a gz extension), v for verbose mode so you can tell what’s going on, f indicating there will be a filename to follow. You may want to create an alias called “untar” that feeds in these options if you have a hard time remembering command line options as I do.

The command will not install the software, but it will extract the archived files. After extracting files then you can install the extracted files by reading README file or INSTALL file (because there you can instructions for installing those particular files).

BASIC LINUX COMMANDS

 

Command	Description
cat [filename]	Display file’s contents to the standard output device (usually your monitor).
cd /directorypath	Change to directory.
chmod [options] mode filename	Change a file’s permissions.
chown [options] filename	Change who owns a file.
clear	Clear a command line screen/window for a fresh start.
cp [options] source destination	Copy files and directories.
date [options]	Display or set the system date and time.
df [options]	Display used and available disk space.
du [options]	Show how much space each file takes up.
file [options] filename	Determine what type of data is within a file.
find [pathname] [expression]	Search for files matching a provided pattern.
grep [options] pattern [filesname]	Search files or output for a particular pattern.
kill [options] pid	Stop a process. If the process refuses to stop, use kill -9 pid.
less [options] [filename]	View the contents of a file one page at a time.
ln [options] source [destination]	Create a shortcut.
locate filename	Search a copy of your filesystem for the specified filename.
lpr [options]	Send a print job.
ls [options]	List directory contents.
man [command]	Display the help information for the specified command.
mkdir [options] directory	Create a new directory.
mv [options] source destination	Rename or move file(s) or directories.
passwd [name [password]]	Change the password or allow (for the system administrator) to change any password.
ps [options]	Display a snapshot of the currently running processes.
pwd	Display the pathname for the current directory.
rm [options] directory	Remove (delete) file(s) and/or directories.
rmdir [options] directory	Delete empty directories.
ssh [options] user@machine	Remotely log in to another Linux machine, over the network. Leave an ssh session by typing exit.
su [options] [user [arguments]]	Switch to another user account.
tail [options] [filename]	Display the last n lines of a file (the default is 10).
tar [options] filename	Store and extract files from a tarfile (.tar) or tarball (.tar.gz or .tgz).
top	Displays the resources being used on your system. Press q to exit.
touch filename	Create an empty file with the specified name.
who [options]	Display who is logged on.