Ubuntu – Linux Useful commands Editor: Nguyen Duc Minh Khoi Email: [email protected] Website: http://nguyenducminhkhoi.blogspot.com HCMC University of Technology @ Summer 2013 Main reference: Ubuntu Linux Toolbox by Christopher Negus François Caen
Aug 29, 2014
Ubuntu – Linux Useful commands
Editor: Nguyen Duc Minh Khoi Email: [email protected] Website: http://nguyenducminhkhoi.blogspot.com HCMC University of Technology @ Summer 2013 Main reference: Ubuntu Linux Toolbox by Christopher Negus François Caen
Forward
• This presentation just give you some basic commands to work with Ubuntu – Linux environment, specially for non-developer users.
• If you want to look more information, search on the Internet with the keyword: “Ubuntu x command” or “Ubuntu + function”
• Please refer to the main reference as much as possible you can
• If you have opportunity, you should buy the main reference book because it explains clearly for you to understand.
• I just give you some examples taken from that book for you to easily lookup as a reference book :D
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Contents
Starting Using Ubuntu
Working as a User
Working as an Administrator
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STARTING USING UBUNTU Section 1
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Basic Linux Commands
• Every Linux Command have this format:
NameOfCommand (Options)* (Argument)*
– Options usually start with – or -- character
• Using help message:
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man Command • To find information about a command
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Other useful commands • Print main page descriptions that match keyword
• Using info documents
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Managing Software with APT
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Managing Software with APT (cont.)
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Managing Software with aptitude
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Managing Software with aptitude (cont.)
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Important shortcuts with Shell • Open shell on the new tab: Ctrl + Shift + t • Open new terminal window: Ctrl + Shift + n • Close tab with: Ctrl + Shift + w • Highlight text and copy: Ctrl + Shift + c • Paste it in shame or different window: Ctrl + Shift + v or click center
button on the mouse • Full screen mode: F11 • Zoom in: Ctrl + Shift + +, zoom out: Ctrl + - • Switch among tabs: Alt + 1, Alt + 2, Alt + 3 and so on • Exit the shell: Ctrl + d • Switch to another virtual console: Ctrl + Alt + F1, Ctrl + Alt + F2
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History commands
• List entire history:
• Search for a string in history:
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Redirect stdin and stdout
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Redirect stdin and stdout (cont.)
• To append a file instead of overwrite it:
• Direct output stream to a special bucket file:
• Pipe with ls commands
• Pipe and redirection combine:
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Using Alias • List Alias that are currently set:
• Define your own alias for the current bash section:
• Remove an alias:
• Remember: Use tab key for suggestions
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Other Useful Commands
• Acquiring Super User Power
• Using Environment Variable: – Display all environment Variable:
– Set or reset variable yourself:
– Concatenate a string with existing variable:
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Using regular files
• Regular files consist of data files (documents, music, images, archives, and so on) and commands (binaries and scripts)
• Use the file commands to see some file types:
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Using regular files (cont.)
• Using directories
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Setting File/Directory Permissions
• Changing permission with chmod
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Setting File/Directory Permissions (cont.)
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Other useful commands
• Changing ownership
• The traversing the File System
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Other useful commands (cont.) • Copying files:
– -a: copying all files, retaining ownership and permission settings
• Finding files with locate
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WORKING AS A USER Section 2
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Matching using regular expression
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Editing text files with nano Editors
• Control keys for nano
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Nano Editors (cont.)
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Listing text file
• Output top 10 lines of a file
• View ends of a file
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Searching for Text with grep – $ grep francois myfile.txt #Show lines containing francois
• Recursive search – $ grep -R VirtualHost /etc/httpd/conf*
• Find the exact lines – $ grep -Rn VirtualHost /etc/httpd/conf*
• Ignore the case – $ grep -i selinux /var/log/messages #Search file for
selinux (any case)
• Checking word count with wc – $ wc /var/log/dmesg #List counts for a single file
436 3847 27984 /var/log/dmesg
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Other useful commands
• Sort output with sort – $ dpkg-query -l | grep kernel | sort #Sort in alphanumeric
order
– $ dpkg-query -l | grep kernel | sort -r #Sort in reverse
alphanumeric order
• Replacing text with sed – $ cat myfile.txt | sed s/francois/chris/
– $ sed s/francois/chris/g < myfile.txt > mynewfile.txt
• Checking different between 2 files: – $ diff config config.old
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Working with audio
• Install sox:
• Using play command:
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Working with audio (cont.)
• Using ogg123 to play ogg file (install ogg123 package first)
• Using mpg321 to play mp3 file (install mpg321 package first)
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Working with audio (cont.)
• Convert audio files
• Display info about a file
• Delete seconds of sound
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Working with Images
• Install ImageMagick package: $ apt-get install imagemagick
• Getting info about images:
• Converting images:
• Resize image:
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Working with Images (cont.) • Rotate images:
• Add text to images:
• Creating thumbnails:
• Making image fun and weird:
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Browse the Web
• Use elinks package to view
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Transferring files
• Download file with wget:
• FTP server requires login and password:
• Download a single webpage
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Transferring files (cont.)
• Connect to a FTP server with lftp:
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Copying remote files with scp
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Chatting with friends in IRC
• Install IRC package:
• Connect to freenode server:
• Joining the centos IRC channel:
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Configuring SSH
• Install OpenSSH:
• Logging remote with ssh:
• Accessing ssh on different port:
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Mastering time • Your computer running Linux keeps time in two different
ways: – a system clock (which Linux uses to keep track of time)
– a hardware clock (that sets the system time when Linux boots up).
• Change current time zone:
• Change system date and time
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Mastering time (cont.)
• Displaying and Setting on your system clock
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Mastering time (cont.)
• Display dates by month
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Mastering time (cont.)
• View the current time from hardware clock:
• Reset your system clock:
• Set hardware clock from system clock:
• Using network time:
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WORKING AS AN ADMINISTRATOR Section 3
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File system basics
• The ext3 file system type is based on the ext2 file system type, adding a feature called journaling to its predecessor.
• Journaling can improve data integrity and recovery, especially after unclean system shutdowns.
• Time-consuming file system checks are avoided during the next reboot after an unclean shutdown, because the changes that occurred since the most recent write to disk are saved and ready to be restored.
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Work with partitions
• Work with specific disk:
• Copying partition tables with sfdisk:
• Creating and using swap partition:
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Listing Active Process
• Use ps and top commands
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Listing Active Process (cont.)
• Custom view Processes:
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Watching active Process with top
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Finding and Controlling Processes
• Using grep:
• Using fuser
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Changing Running Process
• Adjust process priority with nice
– nice value that can be used to tell the Linux process scheduler what priority should be given to that process.
– The default nice value is 0. You can use the nice command to run a process at a higher or lower priority than the default. The priority number can range from –20 (most favorable scheduling priority) to 19 (least favorable scheduling priority).
– Although the root user can raise or lower any user’s nice value, a regular user can only lower the priorities of a process (setting a higher nice value).
– See current nice value
– Changing nice value:
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Changing Running Process (cont.)
• Changing process nice value:
• Running process in background and foreground
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Changing Running Process (cont.) • Manage background jobs:
• Kill process:
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Monitoring Resources • First install sysstat package:
• See how much memory is being used
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Monitoring Resources (cont.)
• View memory used over a give period:
• View info about processor itself
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Monitoring Resources (cont.)
• List info about disk reads and writes
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Managing network interface card
• Use ethtool command:
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Managing network interface card (cont.)
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Ethernet connection • Show address info and status of eth0 Ethernet interface:
• Get information both active and inactive NICs
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Ethernet connection (cont.)
• See info on all interfaces:
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Troubleshooting network problems
• Make sure there is IP - connectivity to that gateway
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Troubleshooting network problems (cont.)
• Check your default gateway:
• Tracing route to host:
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Display netstat connections
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Working with user and groups
• Adding user accounts:
• Create new users with home directory: /home/willz
• Add password:
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Working with user and groups (cont.)
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Modifying User account
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Modifying User account (cont.)
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Managing passwords
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Working with groups
• Getting info about user log on system:
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Checking on Users
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THANKS FOR WATCHING Khoi Nguyen ([email protected]) @ HCMUT 2013
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