Ubuntu, Linux - cmds, utils etc.

Finding the current version of ubuntu

• uname -mrs
• lsb_release -a
• cat /etc/issue

How to upgrade to latest ubuntu

• sudo apt-get update
• sudo apt-get upgrade
• sudo apt-get dist-upgrade

Then begin the upgrade process

• sudo apt-get install update-manager-core
• sudo do-release-upgrade
  • sudo do-release-upgrade -d (if No new release found msg pops up)
• http://www.cyberciti.biz/faq/howto-upgrade-to-ubuntu-14-04-from-ubuntu-13-10-or-12-04
• http://lawrit.lawr.ucdavis.edu/it-help-center/how-to/upgrading-ubuntu-via-command-line

Switching terminals

• Ctrl + Alt + F1….F7
  • F7 - desktop

Hibernating, Suspend system

• sudo pm-suspend
• sudo pm-hibernate

Details for processor

• cat /proc/cpuinfo

Battery Charge details

• acpi

Listing all attached drives

• sudo fdisk -l

Making bootable usb stick

• http://superuser.com/questions/591234/creating-a-bootable-usb-from-command-line-on-linux
• http://askubuntu.com/questions/372607/how-to-create-a-bootable-ubuntu-usb-flash-drive-from-terminal

Commands

• man -k
• id, groups, useradd, userdel, groupadd, groupdel
• /etc/passwd, /etc/group,
• usermod - modify user accounts
• history, tail, head
• ./bash_profile
• alias
• env, set, export, $HOME, $SHELL,

network tools

• host for ip address
• nslookup
• dig
• ifconfig up/down
• ip addr show
• ip route show
• route -n (to show route table)
• traceroute
• nc -v -z hostname 80-1000 2>&1 /to scan ports (80 to 100) on hostname
• nc -k -l 4000 //to listen for connections on port 400
• nc hostname 4000 //to connect to hostname on port
• netstat -(all(a), tcp(t), udp(u), listen(l), process(p), userid(e)) //e.g nestat -atp (all tcp with process name)

command line utils

• cat, tac, Ctrl+D
• sed s/pattern/replace-patter/g
• awk -F: ‘{print $0..$6}’ file , -F: => use ‘:’ as field seperator
• sort file
• uniq file => uniq consecutive line entries in a file
• paste file1 file2
• grep [pattern] file
• tr ‘from’ ‘trom’ < file

• ls -l

  tee file.txt => prints to stdout and also to file.txt

• wc => word count
• less, head, tail

• du -sh *

  sort -n (for list directories and their sizes in human readable format)

bash utils/hacks

• alias
  • ‘alias’ just for listing existing alias
  • setting up alias -> alias = ‘cd /usr; ls; cd -‘ use semicolon to seperate mutiliple commands
  • ‘unalias’ to reverse the association

I/O redirection

• ls -l /usr > abcd.txt (stdout to abcd.txt)
• ls -l /usr » abcd.txt (append stdout to abcd.txt)
• ls -l /usr 2> error.txt (stderror to error.txt)
• ls -l /usr &> out.txt (stdout and stderror to out.txt)
• ls -l /bin/usr 2> /dev/null (disposing std error)
• cat < lazy_dog.txt (changing stdinput for cat to contents of lazy_dog.txt)

Listing directory sizes

• ncdu