CS469/569 - Linux and Unix Administration and Networking

Commands:

Command	What it does
`man`	Read the online manual pages
`ls`	List files
`cd`	Change directory
`cp`	Copy files
`mv`	Rename / move files
`rm`	Remove file
`mkdir`	Make a directory
`rmdir`	Remove empty directory
`chmod`	Set permissions on file or files.
`chown`	Set ownership on files.
`chgrp`	Set group ownership on files.
`touch`	Updates last access and modification times of files, creating new files if necessary.
`getfacl`	Display the ACLs on a file or files
`setfacl`	Set/update the ACLs on a file or files
`ln`	Make links (symbolic or hard) between files.
`cat`	Concatenate files
`more/less/most`	Paginate output of files
`grep`	Search for pattern in files.


`kate`	The best Unix text editor
`jove`	The best text-mode Unix text editor
`vi`	The default Unix text editor for some reason
`emacs`	A heavy-weight text-mode text editor
`nano`/`pico`	A simple text editor
`ne`	A Nice Editor

Command	What it does
`df`	Displays mounted file-systems and information about them
`umask`	Set/show the default file/directory permissions creation mask.
`readlink`	Print the value of a symbolic link.
`realpath`	Print the real resolved path from the path given.
`head`	Print first (10) lines in a file.
`tail`	Print last (10) lines in a file.
`zcat / zgrep / gzip`	Performs ops on gzipped files.
`file`	Identifies the type of a file file is.
`find`	Search for files in a directory hierarchy
`locate`	Search for files indexed in a location database (much faster than find)
`tree`	Display files and directories in a depth indented listing
`sed`	Stream editor for filtering and transforming text.
`printenv`	Displays the current environment.
`dd`	Convert and copy files
`init/telinit`	Change runlevel.
`runlevel`	Displays the current runlevel
`shutdown`	Halt (-h) or reboot (-h) the system.

Command	What it does
`true`	Always succeeds (true)
`false`	Always fails (false)
`sort`	Sort the lines in a file.
`uniq`	Filters out adjacent matching lines.
`basename`	Strip the directory name [and suffix] from a filename.
`dirname`	Strip last component from filename.
`tr`	Translate or delete characters
`tac`	Cat files in reverse
`colrm`	Remove columns from a file.
`cut`	Remove sections from each line of a file.
`tee`	Read from stdin and write to stdout and files
`env`	Run a program in a modified environment.
`date`	Print or set system date and time.

Command	What it does
`declare`	Declares variables of a specific type
`let`	Defines integer variables, performs C like arithmetic expressions.
`local`	Makes variables local to a function, otherwise variables are global by default.
`export`	Makes a variable part of the environment
`unset`	Unset the variable (default or -v) or function (-f).
`alias`	Creates an command alias.
`bg`	Continues a stopped process in the background.
`fg`	Brings a job to the foreground.
`jobs`	Lists jobs, both running and stopped.
`echo`	Prints to the output, or a newline if strings is omitted.
`printf`	Like the C printf function
`read`	Reads a line of text and splits it according to IFS and assigns words the variables listed.
`test`	Same as [...] and mostly [[...]]
`source` / `.`	Reads and executes in the current shell.
`ulimit`	Set resource limits.

Command	What it does
`ps`	Report snapshot of current processes
`pstree`	View processes in a tree like format
`top/htop`	View processes continously
`kill`	Send a signal to a process or processes.
`killall`	Send a signal to a process or processes by name
`pgrep`	Look up processes based on name and other attributes.
`pkill`	Signal processes based on name and other attributes.
`ldconfig`	Maintains links to shared libraries and updates the linker cache files
`ldd`	Lists the shared library/objects used by a particular program.
`nm`	lists symbols from an object.
`ar`	Create/modify and extract from archives (.a files).
`strace`	Trace syscalls made by a running executable.
`nice`	Start a program at a specific niceness
`renice`	Set the niceness of a running process.
`ionice`	Get/Set I/O scheduling class and priority
`limit/ulimit`	Set resource limits. (shell builtins)

Command	What it does
`fdisk`	Partition a disk
`parted`	Partition a disk (supports GPT)
`mkswap`	Initialize a swap parition or file
`swapon`	Enable swapping on devices
`swapoff`	Disable swapping
`swaplabel`	Show/set swap label
`mount`	Maps a filesystem into the directory hierarchy.
`umount`	Removes a file-system from the directory hierarchy (un-mounts a filesystem.)
`fuser`	Display processes (& users -u) using files, filesystems (-m) or sockets (-n).
`lsof`	Like fuser, but more. Lists open files for all processes.
`mkfs.*`	Make a filesystem
`mke2fs`	Make an ext[234] filesystem.
`fsck.*`	Check and repair a file-system
`e2fsck`	Check and repair a Linux ext[234] filesystem.
`badblocks`	Check device for bad blocks.
`e2label`	Display or change the label on a ext* filesystem.
`tune2fs`	Tune the file-system parameters on ext* file-systems.
`mknod`	Make a device file
`iostat`	Display CPU and disk I/O stats.
`vmstat`	Display virtual memory statistics.
`mdadm`	Linux MD (RAID) administration tool

Command	What it does
`useradd`	Adds a user to the system
`userdel`	Delete a user
`usermod`	Modify user
`adduser`	Script wrapper to useradd
`newusers`	Add users in bulk
`chfn`	Change finger (gecos) information.
`chsh`	Change default login shell.
`passwd`	Change password for a user.
`chpasswd`	Change passwords in bulk
`chage`	Change password expiration for a user.
`groupadd`	Add a group to the system
`groupmod`	Modify a group on the system
`groupdel`	Delete a group on the system
`gpasswd`	Change a group password
`vipw`	Edit passwd / shadow (`-s`) file
`vigr`	Edit group / gshadow (`-s`) file
`sudo`	Execute a command or start an interactive shell as another user (by default root.)
`su`	Switch user
`newgroup`	Switch group
`sg`	Like newgroup but accepts a command
`id`	Display current user/uid and group names/gid's.
`groups`	Display current group memberships
`last`	Display last logins in reverse order.
`sac / ac`	System login accounting, displays login accounting (usage.)
`finger/w/who/users`	Display who is currently logged in.

Command	What it does
`klogd`	System daemon that logs kernel messages (usually through the syslog facility.)
`dmesg`	Prints kernel messages to the console.
`syslogd`	System logging daemon
`logger`	Command line tool to log messages to the syslog facility.
`logrotate`	Rotate/compress/mail system logs

Command	What it does
`quotacheck`	Check and update quota files.
`quotaon`	Enable quotas on a file-system or (`-a`) all file-systems.
`quotaoff`	Turn quotas off on a filesystem or (`-a`) all file-systems.
`quota`	Display user or group quota
`edquota`	Edit user/group quota
`setquota`	Command line quota editor
`warnquota`	Send email to users over quota
`repquota`	Quota report
`quotastats`	Quota statistics

Command	What it does
`mysql`	The MySQL/MariaDB client command
`mysqldump`	Dumps MySQL / MariaDB databases as SQL
`mysqlshow`	Displays a list of MySQL/ MariaDB databases

Command	What it does
`ssh`	Secure shell to another computer.
`scp`	Copy files using ssh
`sftp`	Secure FTP client
`rsync`	Like scp, but only copies changed files.
`ssh-keygen`	Authentication key generation, management and conversion
`ssh-copy-id`	Install your public key in a remote machine's authorized_keys
`nc`	(netcat) TCP/IP swiss army knife
`curl`	Transfer/get a URL to your local machine via the command line.
`wget`	Non-interactive network down-loader
`arp`	Manipulate and display ARP cache
`hostname`	Set (requires root) or show the systems hostname
`dig`	Another DNS lookup util
`host`	DNS lookup util
`nslookup`	Yet another DNS lookup util (older, almost deprecated.)
`ifconfig`	Configure a network interface (being deprecated)
`ip`	Show/manipulate routing, devices, policy routing and tunnels.
`route`	Print and set routes
`routel`	List routes
`traceroute`	Show routes taken from host to destination.
`ping`	Send ICMP echo's to a machine.