Linux commands

Keys in Linux commands

There are a some different keys types in:

UNIX keys - begin with "-" sign
BSD keys - with no any sign
GNU keys - with "--" sign

There are some operators in Linux commands are listed below:

> - stdout. Remove file content after use.
< - stdin
2> - stderr
>> - append stdout file
&> - stdout and stderror in one file
| - pipe. Use to transfer stdout from one command to another.
$(command) assigns the result of command to some variable

Common commands in shell

Common comands in shell are listed below.

Command	Desctiption
`alias`	Create aliase for some command
`bash`	Start new bash session.
`cat`	Concatenate txt files.
`cp`	Copy files.
`cut`	Remove sections from each line on files.
`command`	Run `$com` directly without alias
`dmesg`	Print or control the kernel ring buffer.
`du`	Estiamte file space usage.
`echo`	Display inputted text in stdout
`getent`	Get entries from name service switch libraries.
`less`	Reader for files whos contains page lister, find text pattern and more
`lsb_release`	Print distribution specific information
`ldd $/bin/sh`	Show shared library required by program
`hostname`	Show or set the system host name.
`locate`	Show where specific file can be stored
`ls`	List files in directory. Also have keys to sort results.
`lsof`	List open files.
`mkdir`	Create a directory.
`mktemp`	Create a temp file in /tmp
`printenv`	list all environment variables
`sort`	Sort files and his content
`sudoedit`	Execute editor which was in $EDITOR.
`stat`	Display information about file or file system
`stty`	Display information about current terminal
`read`	Read data from stdin.
`rm`	Remove file.
`rmdir`	Remove directory
`tac`	Concatenate txt files in reverse order.
`tee`	Print stdput on console and write stdout to file simultaniously.
`tree`	List contents of directories in tree format
`touch`	Change file timestamps. Create file if it not exist.
`tr`	Translate or delete characters
`type`	Show information about command (location of command)
`ulimit`	Provide control over the available resources.
`uname`	Print system information.
`updatedb`	Update DB for `locate` program
`vipe`	Pipe to text editor (inhabit in `moreutils` packages)
`watch`	Execute a given command periodically.
`which`	Show the full path of (shell) commands.
`xclip`	Copy from shell to clipboard (Not in coreutils)

Working with text files

Comands for work with text files in shell are listed below.

Command	Desctiption
`cat`	Concatenate file with another one.
`grep`	Find text pattern in file(s).
`head`	Show only few top lines of the file.
`tail`	Show only few bottom lines of the file
`wc`	Count number of rows, words, and other in file.

Users. Groups. Access Rules.

Comands for work with users, groups and access rules in shell are listed below.

Command	Desctiption
`chage`	Change user password expiry information.
`chgrp`	Change group ownership.
`chfn`	Change personal information about user (full name, phone, etc).
`chown`	Change file owner and group.
`chmod`	Change file mode bits.
`getfacl`	Get file access control lists.
`groupadd`	Create a new group.
`groupmod`	Modify exist group.
`groupdel`	Delete group.
`gpasswd`	Administer groups.
`groups`	Print the groups are user is in.
`id`	Print user id and group IDs.
`lid`	Display user groups or group users.
`mkpasswd`	Encrypt the given password with given crypt and optionaly with given salt
`passwd`	Update user authentication tokens.
`setfacl`	Set file access control list.
`su $usr`	Run command with substitute $usr and group ID.
`sudo`	Execute a command as another user.
`umask`	The user file-creation default mask.
`useradd`	Create a new user or update default new user information.
`userdel`	Delete user.
`usermod`	Modify information about exist user.
`visudo`	Allow to change /etc/sudoers file

Working with hardware without disks

Comands for working with hardware in shell are listed below.

Command	Desctiption
`iostat`	Report CPU statistics and IO statistics from devices and partitions.
`lscpu`	Display information about cpu.
`lspci`	List al PCI devices.
`lsmod`	Show the status of modules in Linux kernel.
`lsusb`	List all USB devices.
`lshw`	List hardware.
`modinfo`	Show information about linux kernel module.
`modprobe`	Add and remove modules from kernel.

Working with disks and filesystems.

Comands for working with disks and filesystems in shell are listed below.

Command	Desctiption
`blkid`	Command-line utility to locate/print block device attributes.
`df`	Report file system disk space usage.
`cfdisk`	Display or manipulate a disk partition table.
`fdisk`	Manipulate disk partition table.
`fsck`	Check and repair the Linux filesystem.
`lsblk`	Show blk hardware (disks)
`lsscsi`	List scsi devices or hosts.
`mkfs`	Create new file system on the partition.
`mount`	Mount filesystem on the partition.
`tune2fs`	Show detailed information about filesystem. Also can tune that filesystem.
`resize2fs`	Re-write metadata of the filesystem.
`umount`	Unmount filesystem from the partition.
`xfs_repair`	Check and repair the xfs filesystem.
`wipefs`	Wipe a signature from a device.

LVM

Comands for working with LVM in shell are listed below.

Command	Desctiption
`lvconvert`	Change logical volume layout.
`lvcreate`	Create logical volume for futher work with it in LVM.
`lvdisplay`	Show detailed information about certain LVM logical volume.
`lvextend`	Extend exist LVM logical volume.
`lvremove`	Remove LVM logical volume.
`lvs`	Display exist LVM logical volumes.
`pvcreate`	Create physical volume for futher work with it in LVM.
`pvdisplay`	Show detailed information about certain LVM physical volume.
`pvremove`	Remove LVM physical volume.
`pvs`	Display exist LVM physical volumes.
`vgcreate`	Create volume group for futher work with it in LVM.
`vgremove`	Remove LVM volume group.
`vgs`	Display exist volume groups.
`vgdisplay`	Show detailed information about certain volume group.
`vgextend`	Extend exist volume group.

Linux software based RAID.

Comands for working with linux software based RAID in shell are listed below.

Command	Desctiption
`mdadm`	Manage RAID devices.

Working with packages.

Comands for work with users, groups and access rules in shell are listed below.

Command	Desctiption
`apt`	Packet manager for Debian based system. Can search, manage and querry information about packages.
`apt-cache`	Query information about installed as well installable packages.
`apt-get`	Search, install, upgrade, remove packages.
`apt-get install --only-upgrade <package_name>`	Upgrade particular package