1.11 Linux

https://www.professormesser.com/free-a-plus-training/220-1102/220-1102-video/220-1102-training-course/

 

 

 

 

 

 

Linux Commands

 

 

Linux commands

 

 

• The command line - Terminal, Xterm, or similar
• Commads are similar in both Linux and masOS - macOS derived from BSD (Berkeley software Distribution) Unix, (macOS is derived from Unix Linux)
• Download a Live CD or install a virtual machine - Many pre-made Linux distributions are available
• Use the 'man' command for help - An online manual > 'man grep'

 

 

 

 

 

 

 

 

 

ls

List directory

 

 

ls and ls -l

 

 

• List directory contents - Similar to the 'dir' command in Windows
• Lists files, directories - May support color coding, Blue is a directory, red is an archieve files, etc
• For long output pipe through more - '> ls -l | more' (use 'q' or 'Ctrl-c' to exit)
• ('| more': to present the output one page at a time)

 

 

 

 

 

 

 

 

 

pwd

 

 

pwd

 

 

• Print Working Directory - Displays the current working directory path, Useful when changing directions often

Windows - cd

 

 

 

 

 

 

 

 

 

mv

 

mv

 

• Move a file - Rename a file
• 'mv source dest' - ex) mv first.txt second.txt
• -> remain only second.txt

 

 

 

 

 

 

 

 

 

 

 

cp

 

 

cp

 

 

• Copy a file - Duplicate files or directories
• 'cp source dest' - ex) cp first.txt second.txt
• -> remain both, first.txt and second.txt

 

 

 

 

 

 

 

 

 

 

 

 

rm

 

 

rm

 

 

• Remove files or directories - Deletes the files
• Does not remove directories by default - Directories must be empty to be removed or must be removed with '-r'

 

 

 

 

 

 

 

 

 

 

 

 

 

chmod

 

 

chmod

 

 

• Change mode of a file system object
• r = read (4), w = write (2), x = execute (1)
• Can also use octal notation
• Set for the file owner(u), the group(g), other(o), or all(a)
• 'chmod mode FILE' - ex) chmod 744 script.ssh
• ex) drwx------ => directory user: 7, group: 0, others: 0 | -rwxr--r-- => user: 7, group: 4, others: 4
• ex) 'chmod a-w first.txt' : all users, no writing to first.txt
• ex) 'chmod u+x script.ssh : The owner of script.ssh can execute the file

 

 

 

 

 

 

 

 

 

 

chown

 

• Change file owner and group - Modify the settings
• 'sudo chown [OWNER:GROUP] file' > ex) 'sudo chown professor first.txt'
• 'sudo' requires additional rights and permissions

 

 

 

 

 

 

 

 

 

 

 

su / sudo

 

• Some command require elevated rights - There are some things normal users can't do
• 'sudo' - Execute a command as the superuser, OR as a different user ID, The specified command executes as the super user
• 'su' - Become super user, Or change to a different user, You continue to be that user until you 'exit'

 

 

 

 

 

 

 

 

 

 

 

 

 

 

apt-get

install/uninstall

 

apt-get

 

 

• Advanced Packaging Tool - Handles the management of application packages, Applications and utilities
• Install, update, remove - ex) 'sudo apt-get install wireshark'

 

 

 

 

 

 

 

 

 

 

 

 

yum

When you can't use 'apt-get' based on one of the Red Hat versions of Linux

 

 

• Yellowdog updater, Modified (yum) - Install, delete, update
• Manage RPM packages - Red Hat Package Manager, RPM Package Manager
• A Linux distribution will commonly use either 'yum' or 'apt-get'

 

 

 

 

 

 

 

 

 

 

 

 

 

ip

 

 

 

 

 

 

 

 

 

• Manage the network interfaces - Enable, disable, configure addresses, manage routes, ARP cache, etc
• ip address - View interface addresses
• ip route - View the IP routing table
• 'sudo ip address add ip address/subnet mask dev the name of the adapter'
• ex) 'sudo ip address add 192.168.121.241/24 dev eth0', Configure the IP address of an interface

dev: device

 

 

 

 

 

 

 

 

 

 

 

 

 

 

df

 

 

df

 

 

 

df -h

 

 

 

 

• Disk free - View file systems and free space
• 'df' - View number of blocks -> may not be very intuitive
• 'df -h' - View human-readable sizes -> much understandable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

grep

 

 

grep

 

 

• Find text in a file - Search through many files at a time
• 'grep PATTERN [FILE]' - ex) grep failed auth.log

 

 

 

 

 

 

 

 

 

 

 

 

ps

 

 

 

 

• View the current proccesses - And the process ID (PID), Similar to the Windows Task Manager
• View user processes - 'ps' -> just the processes running for yourself or your user name
• View all processes - 'ps -e | more'

 

 

 

 

 

 

 

 

 

 

 

 

top

 

 

top

 

 

• View CPU, RAM, and resource utilizations - The 'Task Manager' for Linux
• Process information - Easy to find the highly utilized applications
• Summary of overall load - One, five, fifteen minutes
• Many different options - Check the man page for startup options and keys

 

 

 

 

 

 

 

 

 

 

 

 

 

find

 

 

find

 

 

• Find a file by name or extension - Search through any or all directories
• Find files with a specific extension - ex) 'file . -name "*.txt"'
• . : where you'd like to begin the search | period(your current folder)
• * : all of the file
• "*.txt" : specify the name of the file you're looking for

 

 

 

 

 

 

 

 

 

 

 

dig

 

 

dig

 

 

• Lookup information from DNS servers - Canonical names, IP addresses, cache timers, etc
• 'dig' (Domain Information Groper) - Detailed domain information, Add 'dig' to Windows

 

Windows: nslookup

 

 

 

 

 

 

 

cat

 

 

Copy files to another file

 

 

 

 

 

Copy a file to the screen

 

 

 

 

• Concatenate - Link together in a series
• Copy a file/files to the screen - ex) 'cat file1.txt file2.txt'
• Copy a file/files to another file - ex) 'cat file1.txt file2.txt > both.txt'
• -> group a file or files to one file (everything contents is one file)

 

 

 

 

 

 

 

 

 

 

 

 

nano

 

nano

 

 

• Full-screen text editor - Easy to edit
• Included with many Linux distributions - Easy to install
• Select, mark, copy/cut, and paste text - Similar features to graphical-based editors
• Ctrl+O : save

 

 

 

 

 

 

 

 

 

 

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Linux Feature

 

 

 

Backups

 

 

backup

 

 

 

tar

 

 

 

 

• Many options - Command line and graphical, May be included with the distribution
• 'tar' - Tape Archive, Easy to script into a backup schedule - zip
• 'rsync' - Sync files between storage devices, Instant synchronization or scheduled
• Command line tools - 'apt-get', 'yum'
• Graphical update managers - Software updater
• Patch management - Updates can be scheduled
• Software center - The Linux "App store"

 

 

tar [options] [archive-fike] [file or directory to be archived]

tar reference

• [options] : Optional flags or settings that modify the behaviour of the tar command.
• [archive-file] : The name of the archive file you are creating or working with.
• [file or directory to be archived] : The file or directory you want to include in the archive.

 

 

 

 

 

 

 

Anti-virus / Anti-malware

 

 

Install ClamAV

 

 

How to install ClamAV

 

 

• Relatively few viruses and malware for Linux (masOS as well) - Still important to keep updated
• Clam Antivirus (ClamAV) - Open source antivirus engine 
• Some best practice as any other OS - Always update signature database, Always use real-time scanning

 

 

 

 

 

 

 

 

 

 

 

 

Shell / Terminal

 

 

Terminal

 

 

• Command line across to the OS - Common to manage in Linux
• OS maintenance - Run script, manage files, Configure OS and application settings
• (Linux user or administering a Linux)

 

 

 

 

 

 

 

 

 

 

Samba

 

 

Install Samba

 

 

 

 

 

 

Samba File

 

 

 

 

 

• Add SMB (Server Message Block) to Linux - File and print sharing (to Windows), Active Directory integration
• Integrate Linux tnto a Windows environmnet - Linux becomes a Windows file server

SMB: a protocol used by Windows to transfer files, access network shares, or print to a network printer