Basic Linux words we should know
Hello, Friends this article will tell you about the important words which come across when we are using Linux.This article will help you to understand more about Linux. If you guys come across some words which are not in this article please do mention those words in your comment and i will make sure that word is in this article.
Arch Linux: – In Linux Dictionary this word means Arch Linux is an i686−optimized Linux distribution. It is lightweight and contains the latest stable versions of the software. Packages are in a .tar.gz format and are tracked by a package manager that is designed to allow easy package upgrades. Arch is designed to be streamlined while allowing for a customized configuration, with newer features such as reiserfs/ext3 and devfs.
Access Control List (access, ACL): – In Linux Dictionary this word means Controlling access not only the system in general but also resources within the system. For example, firewalls can be configured to allow access to different portions of the network for different users. Likewise, even after you log onto a file server, the server may still block access to certain files. Key point: An Access Control List (ACL) is used to list those accounts that have access to the resource that the list applies to.
Alias: – In Linux Dictionary this word means A secondary or symbolic name for a file, a collection of data, or a computer device. In a spreadsheet, a range name, such as Income, is an alias for a range, such as A3..K3. In networks, group aliases provide a handy way to send electronic mailed two or more people simultaneously.
append: – In Linux Dictionary this word means To place after, or at the end of, a character, a line, or a file. In the vi editor, certain commands let you append text in a document. In the Bourne and C shells, the symbol >> allows you to append output to an existing file (or create a new file if the file does not yet exist).
Apache: – In Linux Dictionary this word means The Apache HTTP Server, colloquially called Apache, is the world’s most used web server software. Originally based on the NCSA HTTPd server, development of Apache began in early 1995 after work on the NCSA code stalled. Apache played a key role in the initial growth of the World Wide Web, quickly overtaking NCSA HTTPd as the dominant HTTP server, and has remained most popular since April 1996. Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.
ark:- In Linux Dictionary this word means An archiver for KDE An archiver for KDE Supports: zip, tar, tar + compression (lzop, gzip, bzip2,
bzip, compress) lha, zoo, rar, ar, etc
$BASH environment variable
In Linux Dictionary this word means Expands to the full pathname used to invoke this instance of bash.
Bash (Bourne Again Shell ): – In Linux Dictionary this word means Bash is a Unix shell and command language written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell. Bash is a command processor that typically runs in a text window, where the user types a command that causes actions. Bash can also read commands from a file, called a script. Like all Unix shells, it supports filename globbing (wildcard matching), piping, here documents, command substitution, variables and control structures for condition-testing and iteration.
boolean: – In Linux Dictionary this word means An Expression−based system that uses the operators AND, OR, and NOT; operations are based on
variables which can be 1 (true) or 0 (false). Booleans allow parts of SELinux policy to be changed at runtime, without any knowledge of SELinux policy writing. This allows changes, such as allowing services access to NFS volumes, without reloading or recompiling SELinux policy.
BIOS: – In Linux Dictionary this word means Basic Input/output System: services on a ROM chip that enable the hardware and software of a
computer to communicate with each other.
bridge: – In Linux Dictionary this word means Any device that connects two physically distinct network segments, usually at a lower network layer
then would a router.
broadcast addresses: – In Linux Dictionary this word means A broadcast address is a logical address at which all devices connected to a multiple-access communications network are enabled to receive datagrams. A message sent to a broadcast address is typically received by all network-attached hosts, rather than by a specific host. In Internet Protocol Version 4 (IPv4) networks, broadcast addresses are special values in the host-identification part of an IP address.
broadcast: – In Linux Dictionary this word means The term “broadcast” is generic and is used in many different areas. The origin of the term obviously
means to cast out broadly, such as a radio broadcast. Subdefinition: Ethernet has broadcast domains,
allowing you to partially sniff some data from your neighbors, and possibly subvert it.
BSD (Berkeley Software Distribution): – In Linux Dictionary this word means A version of the UNIX operating system that was developed and formerly maintained by the University of California, Berkeley. BSD helped to establish the Internet in colleges and universities
because the distributed software included TCP/IP.
chmod: – In Linux Dictionary this word means changes the permissions for a file; permissions should include a letter designating who gets
permissions (u for the user, g for the group, o for others, or a for all) followed by a + or − (to give or take away the permission) followed by the kind of permission (r for read access, w for write access, x for execute if the file is a program or script).
chown- In Linux Dictionary this word means changes the user and/or group ownership of each given file as specified by the first non−option
argument as follows.
Cron: – In Linux Dictionary this word means management of regular background processing cron is a background process (`daemon’) that runs
programs at regular intervals (for example, every minute, day, week or month); which processes are
run and at what times are specified in the `crontab’.
datagram: – In Linux Dictionary this word means A packet which includes both the source and destination addresses provided by the user, and not the network. Datagrams can also include data.
DES (Data Encryption Standard, FIPS 46−3)
In cryptography, DES (Data Encryption Standard) is the most popular algorithm for encrypting data. It is standardized by the United States government (ANSI X9.17) as well as the ISO. Key point: DES ushered in a new era of cryptography. Before DES, strong encryption was only available to large governments and militaries. Cryptography research was similarly limited. Anything that the average person might use could easily be cracked by a major government. DES created a well−defined, easily verifiable security architecture that was available to anyone.
Dev: – In Linux Dictionary this word means The Red Hat Linux operating system uses file system entries to represent devices (CD−ROMs, floppy drives, etc.) attached to the machine. All of these entries are in the /dev tree (although they do not have to be). This package contains the most commonly used /dev entries. The dev package is a basic part of your Red Hat Linux system and it needs to be installed.
eth0: – In Linux Dictionary this word means first ethernet interface. (Additional ethernet interfaces would be namedeth1, eth2, etc.) This type of interface is usually a NIC connected to the network by a category 5 cable.
Hard Link: – In Linux Dictionary this word means Hard link is a bit different object when compared to a symlink. In the soft link, a new file and a new Inode is created, but in the hard link, only an entry into directory structure is created for the file, but it points to the inode location of the original file. This means there is no new inode creation in the hard link.
$HISTFILE environment variable
In Linux Dictionary this word means The name of the file in which command history is saved. (See HISTORY below.) The default value is ~/.bash_history. If unset, the command history is not saved when an interactive shell exits.
init: -In Linux Dictionary this word means In Unix-based computer operating systems, init (short for initialization) is the first process started during booting of the computer system. Init is a daemon process that continues running until the system is shut down.It is the direct or indirect ancestor of all other processes and automatically adopts all orphaned processes.
IP multicast: – In Linux Dictionary this word means IP multicast is a method of sending Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission. It is often employed for streaming media applications on the Internet and private networks. The method is the IP-specific version of the general concept of multicast networking. It uses specially reserved multicast address blocks in IPv4 and IPv6. In IPv6, IP multicast addressing replaces broadcast addressing as implemented in IPv4.
Kdc: – In Linux Dictionary this word means Kerberos is a network authentication protocol. Kerberos provides a strong cryptographic authentication of the devices which lets the client & servers to communicate in a more secure manner. It is designed to address network security problems. When firewalls acts a solution to address the intrusion from the external networks
Kiosk software: – In Linux Dictionary this word means the system and user interface software designed for an interactive kiosk or Internet kiosk. Kiosk software locks down the application in order to protect the kiosk from users. Kiosk software may offer remote monitoring to manage multiple kiosks from another location.
Email or text alerts may be automatically sent from the kiosk for daily activity reports or generated in response to problems detected by the software.
Linux Pluggable Authentication Modules (PAM): – In Linux Dictionary this word means provide dynamic authentication support for applications and services in a Linux or GNU/kFreeBSD system. Linux-PAM is evolved from the Unix Pluggable Authentication Modules architecture.
lo – In Linux Dictionary this word means the loopback interface. This is a special network interface that the system uses to communicate with itself. The most common IPv4 address used is 127.0.0.1.
Netmask: – In Linux Dictionary this word means A netmask is a 32-bit mask used to divide an IP address into subnets and specify the network’s available hosts. A subnetwork, or subnet, is a logical, visible subdivision of an IP network. The practice of dividing a network into two or more networks is called subnetting.
Computers that belong to a subnet are addressed with a common, identical, most-significant bit-group in their IP address. This results in the logical division of an IP address into two fields, a network or routing prefix and the rest field or host identifier.
Network interface controller(NIC card): – In Linux Dictionary this word means a computer hardware component that connects a computer to a computer network. Modern network interface controllers offer advanced features such as interrupt and DMA interfaces to the host processors, support for multiple receive and transmit queues, partitioning into multiple logical interfaces, and on-controller network traffic processing such as the TCP offload engine.
pts – pseudoterminal: – master and slave
A pseudoterminal (sometimes abbreviated “pty”) is a pair of virtual character devices that provide a bidirectional communication channel. One end of the channel is called the master; the other end is called the slave.The slave end of the pseudoterminal provides an interface that behaves exactly like a classical terminal. A process that expects to be connected to a terminal, can open the slave end of a pseudoterminal and then be driven by a program that has opened the master end. Anything that is written on the master end is provided to the process on the slave end as though it was input typed on a terminal.
Root: – In computing, the superuser is a special user account used for system administration. Depending on the operating system (OS), the actual name of this account might be root, administrator, admin or supervisor. On Linux, the user group administrator (admin) consists of non-root users who are allowed root privileges via the command sudo, and so is not the same as root in this instance.
Security-Enhanced Linux(SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including United States Department of Defence–style mandatory (MAC). SELinux is a set of kernel modifications and user-space tools that have been added to various Linux distributions.
Shell Scripting: – Shell Scripting and hence computer programming is merely the idea of getting a number of commands to be executed, that in combination do some unique powerful function.
signal -overview of signals
Each signal has a current disposition, which determines how the process behaves when it is delivered the signal. Signals are a limited form of inter-process communication used in Unix, Unix-like, and other POSIX-compliant operating systems. A signal is an asynchronous notification sent to a processor to a specific thread within the same process in order to notify it of an event that occurred.
Soft Link: – Symbolic links or Symlinks are the easiest to understand because for sure you have used them, at least when you were using Windows. Soft links are very similar to what we say “Shortcut” in windows, is a way to link to a file or directory.
Slabs: – The cache allocator works with the rest of the memory system to maintain a balance between the memory needs of each driver or module and the system as a whole. The Linux 2.4 kernel implements a caching memory allocator to hold caches (called slabs) of identical objects.
skel: – The /etc/skel directory contains files and directories that are automatically copied over to a new user’s home directory when such user is created by the useradd program.
A home directory also called a login directory is a directory on Unix-like operating systems that serves as the repository for a user’s personal files, directories, and programs, including personal configuration files.
Telnet: – An Internet protocol that enables Internet users to log on to another computer linked to the Internet, including those that cannot directly communicate with the internet’s TCP/IP protocols. Telnet establishes a “plain vanilla” computer terminal called a network virtual terminal. This capability is frequently used to enable communications with bulletin boards systems (BBSs) and mainframe computers.
Touch: –change file timestamps and create a file
Increase Transmit Queue Length for 10G NICs with:
/sbin/ifconfig em1 txqueuelen 10000
/sbin/ifconfig em2 txqueuelen 10000
The current size of the transmission queue can be obtained from the ip and ifconfig commands. The length of the transmission queue in Linux defaults to 1,000 packets which are a large amount of buffering especially at low bandwidths.
Vim: – is an editor to create or edit a text file. There are two modes in vim. One is the command mode and another is the insert mode. In the command mode, the user can move around the file, delete text, etc.
wlan0: – is the name of the first wireless network interface on the system. Additional wireless interfaces would be named wlan1, wlan2, etc.