Difference between revisions of "Linux"

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== Commands ==
== Commands ==
 
=== System ===
For use in the service console
{|class="vwikitable"
 
{|cellpadding="2" cellspacing="0" border="1"
|-
|-
|<code> ls -l </code>                    || List directory contents (<code>-l</code> long format) - [http://communities.vmware.com/message/678302#678302 Colour codes]
! Syntax                                  !! Action / Description
|-
|-
|<code> pwd </code>                       || Present working directory
|<code> shutdown -r now </code>           || Restart / reboot system, use <code>-h</code> to shutdown/halt.  If command not available use <code>init</code>
|-
|-
|<code> cp <src> <dest> </code>           || Copy a file
|<code> init <level> </code>             || Level 0 - Halt system, level 6 - Reboot system
|-
|-
|<code> ln -s <src> <dest> </code>       || Create a symbolic link to a file
|<code> uname -a </code>                 || Running OS info
|-
|-
|<code> rm –i <file> </code>             || Remove (delete) file (<code>-i</code> prompts before remove)
|<code> arp -n </code>                   || IP -> MAC arp table
|-
|-
|<code> rm –d -r -f <folder> </code>     || Remove (delete) folder and contents '''without prompting'''
|<code> ifconfig </code>                 || Interface config (Unix equiv of Windows' ipconfig)
|-
|-
|<code> find <folder> -mtime +14 -exec rm {} \; </code>     || Remove (delete) files in folder older than 14 days
|<code> ps fx <nowiki>|</nowiki> grep <proc> </code>       || Find running process info
|-
|-
|<code> more <file> </code>               || Views a file (read only), <code>q</code> to exit, <code>+line</code> to start from line
|<code> ps -aux </code>                   || Running process info
|-
|-
|<code> find /path/ -iname "*FILENAME*" </code> || Find file with ''*filename*'' in ''path''
|<code> kill <pid> </code>               || Kill a process
|-
|-
|<code> watch -d "ls -lt *.vmdk ;date" </code> || Watch modifications occurring to files matching ''*.vmdk''
|<code> top </code>                       || Task Manager (ish)
|-
|-
|<code> diff <file1> <file2> </code>     || Difference between two files
|<code> free -m </code>                   || Free memory
|}
 
=== File System and File Operations ===
{|class="vwikitable"
|-
|-
|<code> grep <find> <file> </code>        || Find all occurrences of ''find'' in ''file''
! Syntax                                  !! Action / Description
|-
|-
|<code> tail <file> </code>               || Displays the last 10 lines of a file, <code>-f</code> follows any updates (eg to monitor a log file)
|<code> ls -l </code>                     || List directory contents (<code>-l</code> long format) - [http://communities.vmware.com/message/678302#678302 Colour codes]
|-
|-
|<code> init <level> </code>             || Level 0 - Halt system, level 6 - Reboot system
|<code> df -h </code>                     || Disk space summary
|-
|-
|<code> df -h </code>                    || Disk space summary
|<code> df -i </code>                    || Disk inodes summary
|-
|-
|<code> du -sh </code>                    || Directory space usage summary
|<code> du -sh </code>                    || Directory space usage summary
|-
|-
|<code> chmod +x <file> </code>          || Add execute permission to a file
|<code> du -ma / | sort -nr | head -n 20 </code>  || Find 20 largest files/directories
|-
|<code> pwd </code>                      || Present working directory
|-
|<code> cp <src> <dest> </code>          || Copy a file (see also <code>[[#SCP|scp]]</code>)
|-
|-
|<code> uname -a </code>                 || Running OS info
|<code> ln -s <src> <dest> </code>       || Create a symbolic link to a file
|-
|-
|<code> arp -n </code>                   || IP -> MAC arp table
|<code> rm –i <file> </code>             || Remove (delete) file (<code>-i</code> prompts before remove)
|-
|-
|<code> ifconfig </code>                 || Interface config (Unix equiv of Windows' ipconfig)
|<code> rm –d -r -f <folder> </code>     || Remove (delete) folder and contents '''without prompting'''
|-
|-
|<code> ps fx <nowiki>|</nowiki> grep <proc> </code>       || Find running process info
|<code> find /path/ -iname "*FILENAME*" </code> || Find file with ''*filename*'' in ''path''
|-
|-
|<code> ps -aux </code>                   || Running process info
|<code> find <folder> -mtime +14 -exec rm {} \; </code>     || Remove (delete) files in folder older than 14 days
|-
|-
|<code> kill <pid> </code>               || Kill a process
|<code> chmod +x <file> </code>           || Add execute permission to a file
|-
|-
|<code> lsof <folder> </code>            || List open files
|<code> lsof <folder> </code>            || List open files
|-
|-
|<code> top </code>                       || Task Manager (ish)
|<code> tar czf file.tgz folder </code>   || Tar contents of folder to file
|}
 
=== File Contents (Inspection and Manipulation) ===
{|class="vwikitable"
|-
! Syntax                                  !! Action / Description
|-
|<code> more <file> </code>              || Views a file (read only), <code>q</code> to exit, <code>+line</code> to start from line
|-
|<code> less <file> </code>              || Views a file (read only), like <code> more </code>, but with increased functionality
|-
|<code> watch -d "ls -lt *.vmdk ;date" </code> || Watch modifications occurring to files matching ''*.vmdk''
|-
|<code> diff <file1> <file2> </code>      || Difference between two files
|-
|-
|<code> free -m </code>                   || Free memory
|<code> grep <find> <file> </code>       || Find all occurrences of ''find'' in ''file''
|-
|-
|<code> tar czf file.tgz folder </code>   || Tar contents of folder to file
|<code> tail <file> </code>               || Displays the last 10 lines of a file, <code>-f</code> follows any updates (eg to monitor a log file)
|}
|}


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== VI Editor ==
== VI Editor ==
 
VI is a bit of a pain to use, go slowly, and use [Esc] regularly to get out of the current mode after each operation.
VI is a bit of a pain to use, go slowly, and use [Esc] regularly to get out of the current mode after each operation  


Crib sheet for VI mode commands...
Crib sheet for VI mode commands...
 
{|class="vwikitable"
{|cellpadding="2" cellspacing="0" border="1"
! Command                              !! Purpose
|-
|-
|<code> i </code>                      || Insert characters
|<code> i </code>                      || Insert characters
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|<code>:undo </code>                    || Undo last action
|<code>:undo </code>                    || Undo last action
|}
|}
== VIM Editor ==
VIm = Vi Improved, the commands are the same, but theres extra features
* [http://www.vim.org/docs.php VIM website]
* [http://vimdoc.sourceforge.net/htmldoc/usr_toc.html VIM on line manual]
=== Installation ===
#  Login to the ESX console using your user account and create a new directory (within <code> /home/user </code>
#* <code> mkdir vim </code>
# Logon to the VCS machine (UKLONVCP1) and copy across the installation files, stored under the Software_Reposity directory (substitute user and ESXserver appropriately).
#* <code> pscp C:\Software_Repository\vim-7.1.tar.bz2 user@ESXserver:/home/user/vim  </code>
# Back on the ESX console become root, change into the directory where vim is
# Extract the package
#* <code>  bunzip2 -c vim-7.1.tar.bz2 | tar -xf - </code>
# Move into the vim71 folder
# Run configure
#* <code> ./configure </code>
# Compile the package
#* <code> make </code>
# Install the package
#* <code> make install </code>
=== Useful Commands ===
{|cellpadding="2" cellspacing="0" border="1"
|-
|<code> :syntax enable </code>                    || Turns on syntax formatting
|-
|<code> vim one.sh two.sh three.sh </code>        || Opens up three files for editing
|-
|<code> :wnext </code>                            || Writes changes to existing file and moves to next file(omit w not to write)
|-
|<code> :wprevious </code>                        || Writes changes to existing file and moves to previous file (omit w not to write)
|-
|<code> v </code>                                || Toggle visual mode (so you can select text), use y/p to yank/paste selected text
|-
|[http://vimdoc.sourceforge.net/htmldoc/usr_07.html#07.5 VIM manual section 7.5] || Copy text between files
|}


== Unix User accounts ==
== Unix User accounts ==
* '''Create Account''' - Use <code> useradd <user> </code> to add a new user account with the default policy settings
* '''Create Account''' - Use <code> useradd <user> </code> to add a new user account with the default policy settings
* '''Modify Password''' - Use <code> passwd <user> </code> to change password for ''user''.  To breach minimum complexity rules you must be logged in at the console (in the DC not remotely)
* '''Modify Password''' - Use <code> passwd <user> </code> to change password for ''user''.  To breach minimum complexity rules you must be logged in at the console (in the DC not remotely)
* '''Modify Expiry''' - To disable the password expiry policy for a account that already exists use <code> chage -M 99999 <user> </code>, to disable for all future account (ie modify the default policy) use <code> esxcfg-auth --passmaxdays=99999 </code>
* '''Modify Expiry''' - To disable the password expiry policy for a account that already exists use <code> chage -M 99999 <user> </code>, to disable for all future account (ie modify the default policy) use <code> esxcfg-auth --passmaxdays=99999 </code>
[[Category:Ubuntu]]

Revision as of 09:44, 7 June 2012

Commands

System

Syntax Action / Description
shutdown -r now Restart / reboot system, use -h to shutdown/halt. If command not available use init
init <level> Level 0 - Halt system, level 6 - Reboot system
uname -a Running OS info
arp -n IP -> MAC arp table
ifconfig Interface config (Unix equiv of Windows' ipconfig)
ps fx | grep <proc> Find running process info
ps -aux Running process info
kill <pid> Kill a process
top Task Manager (ish)
free -m Free memory

File System and File Operations

Syntax Action / Description
ls -l List directory contents (-l long format) - Colour codes
df -h Disk space summary
df -i Disk inodes summary
du -sh Directory space usage summary
sort -nr | head -n 20 Find 20 largest files/directories
pwd Present working directory
cp <src> <dest> Copy a file (see also scp)
ln -s <src> <dest> Create a symbolic link to a file
rm –i <file> Remove (delete) file (-i prompts before remove)
rm –d -r -f <folder> Remove (delete) folder and contents without prompting
find /path/ -iname "*FILENAME*" Find file with *filename* in path
find <folder> -mtime +14 -exec rm {} \; Remove (delete) files in folder older than 14 days
chmod +x <file> Add execute permission to a file
lsof <folder> List open files
tar czf file.tgz folder Tar contents of folder to file

File Contents (Inspection and Manipulation)

Syntax Action / Description
more <file> Views a file (read only), q to exit, +line to start from line
less <file> Views a file (read only), like more , but with increased functionality
watch -d "ls -lt *.vmdk ;date" Watch modifications occurring to files matching *.vmdk
diff <file1> <file2> Difference between two files
grep <find> <file> Find all occurrences of find in file
tail <file> Displays the last 10 lines of a file, -f follows any updates (eg to monitor a log file)

SCP

In order to be able to copy files from one machine to the other... scp user@server:/remote/server/path/file /local/server/path/

In order to be able to copy files within a script (and not get prompted for a user password, the public key of the machine running the script needs to be authorised on the remote server.

  1. On the local machine, be logged in as the same user as will be running the script
  2. Create public key on local machine (just hit return to accept default options)
    • ssh-keygen -t rsa
  3. Copy the public key for local machine user to the remote machine
    • EG scp /root/.ssh/id_rsa.pub server:/home/user/
  4. On the remote machine, check if the following file already exists
    • /root/.ssh/authorized_keys
  5. If so, append the contents of the copied key to the file
  6. If not, copy the file

VI Editor

VI is a bit of a pain to use, go slowly, and use [Esc] regularly to get out of the current mode after each operation.

Crib sheet for VI mode commands...

Command Purpose
i Insert characters
x Delete character
r Replace character
cw Overwrite word (use any delimiter)
o Insert line
dd Delete current line
<x>yy Yank (copy) next x lines (inclusive of current line, default x is 1)
p Paste yanked lines
/<string> Search for next occurrence of string
:g/<find>/s//<replace>/g Find and replace
:wq Write (save) and Quit
:q! Quit (don't save)
:undo Undo last action

Unix User accounts

  • Create Account - Use useradd <user> to add a new user account with the default policy settings
  • Modify Password - Use passwd <user> to change password for user. To breach minimum complexity rules you must be logged in at the console (in the DC not remotely)
  • Modify Expiry - To disable the password expiry policy for a account that already exists use chage -M 99999 <user> , to disable for all future account (ie modify the default policy) use esxcfg-auth --passmaxdays=99999
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