Linux Survival Kit

A list of the most common linux commands. If you are to handle Linux, Apache, or Vi for the first time this can help you

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________..:::.. LINUX SURVIVAL KIT ..:::.._________


(Or how to type commands without really knowing what you're doing...
at first..)


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man
manual
ex: man vi (shows vi manual)
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uname -r
to see actual Linux kernel
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reboot
shutdown -r now
both are to reboot
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halt
shutdown -h now
both are to shutdown the machine
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adduser username
to add an user

userdel username
to delete an user

passwd username
to change the password
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[options]
-R recursive
-f folder
* all files
ex: cp -Rf SOURCE TARGET will copy all files and folder (recursive)
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ls -la
Listing directories

ls -l
view the current permissions on files and directories

ls -a
to list hidden files
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find

find a file: go to root folder
cd /
ex: find httpd.conf
find -name httpd.conf
find -name httpd.*

find a string recursively inside files:

find | xargs grep -r "mysql_query"

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sed

find and replace in file(s), in this example we want to
replace all calls to a funcion utf8_decode() but keeping
the parameter value

if I've got: utf8_decode($myMyStringValue);
I will get: $myStringValue; instead

sed -e 's/utf8_decode(\(.*\))/\1/g' my_file.php


cp

cp SOURCE TARGET
ex: cp httpd.conf httpd_copy.conf
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mv
move/rename a file
ex: mv old_name new_name
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rm

remove files/folders
ex: rm -Rf my_folder (Will remove my_folder and all folders and files under that name)

NEVER rm $Rf / (You will erase all folders & files from the root folder!!!)
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chown
change owner of a file
ex: chown username. filename/directory
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chmod
change permissions
ex: chmod xxx filename/directory
You will have to replace the xxx flags with the permissions you wish to change. You can either go by the numerical value or by the actuals.

Some common numerical values are:
755 - Read, Write, Execute for owner, read, execute for group and other.
644 - Read, Write for owner, read for group and other.
666 - Read, Write for all.
700 - Read, Write, Execute for owner, nothing for group, other.
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mount
to mount a drive
ex to access to a cdrom drive:
mount /dev/cdrom /mnt/cdrom
mount /dev/cdrom /cdrom
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pwd
shows path to actual directory
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su -
Change to system user
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rpm -Uvh filename.rpm
to install a program (RedHat, Mandrake, SuSE
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diff
Compare TWO files
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who
Shows who is connected
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history
Shows a list of command typed for an user
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apt-get install emacs
-- to install emacs (Debian)
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dpkg -l|grep php
-- to see if something is installed and which versions (-l: list)
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whereis
find a command
ex: whereis php5


some colour:Make "ls" command show colors without "--color=always" switch
edit the user .bashrc file
add or edit an alias
alias ls="ls --color=always"
Then give the command:
source .bashrc
That will reload .bashrc
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__TAR: ZIP/UNZIP FILES___


Create -> tar cvzf myfile.tgz origin_files (wildcards admitted)
See files -> tar tzf myfile.tgz
Extract-> tar xvzf myfile.tgz



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___APACHE___


/etc/init.d/apachectl start

/etc/init.d/apachectl restart

/etc/init.d/apachectl stop


--- OR ----

Find Apache bin directory:

1. go to root
cd /
2. Use Find command
find -name apache*
3. Command the service
/usr/local/apache2/bin/apachectl start



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___MySQL__

Command line

/usr/local/mysql/bin/mysql start

ps aux | grep mysql




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VI/VIM COMMANDS
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Key: Action:

Enter command mode
i Enter insert mode to exit mode
R Enter overwrite mode
a Enter append mode
:w Save File
:q Exit vim without saving
x Delete the character under the cursor
dw Delete the current word
dd Delete the current line
d$ Delete everything Right of the cursor
yy Yank the current line onto the clipboard
yw Yank the current word onto the clipboard
p Paste the clipboard
u Undo
^r Redo
G Jump to bottom of file
/text Search for the textfrom the cursor



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___Mail___

cat /dev/null > /var/mail/root

Will delete all mail from user root.
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mutt

Launch email client on the command line
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mailq -v

To check how many pending mail you have
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rm /var/spool/mail/*.*
rm /var/mqueue/*.*

Manually removed pending mails
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sendmail -v -q

Delete pending mails using sendmail command
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$ sendmail -qS -v domainname.com it will delete all mail from *@domainname.com

You can delete certain domain or user or recipient mail using the following command
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$ sendmail -qR -v gmail.com
Delete mail from recipient gmail.com

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$ find /var/spool/mqueue -type f -exec grep "Deferred: Connection refused" {} \; -exec rm -rf {} \;
Use find command to removed queues


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CONSOLE COLORS
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tput setf 4 ( set foreground color to 4)

tput setb 2 (set background color to 2)


* 0 Black
* 1 Red
* 2 Green
* 3 Yellow
* 4 Blue
* 5 Magenta
* 6 Cyan
* 7 White

//-- some other colors

"DarkGreen"
"Sienna"
"RoyalBlue"
"Blue"
"Black"
"Black"
"Purple"
"Wheat"


//-- OPEN EMACS WITH PRESET COLOURS

emacs -bg blue -fg magenta