Apache
htdocs folder
/var/www
apache configuration files
/etc/apache2/
vhosts definitions
/etc/apache2/sites-available
Create a link to each definition in /etc/apache2/sites-enabled:
ln-s /etc/apache2/sites-enabled/mysite.lnk /etc/apache2/sites-available/mysite
Or with newer versions of Ubuntu:
a2ensite mysite
for enabling and
a2dissite mysite
for disabling
start/stop/restart apache
sudo/etc/init.d/apache2 start/restart/stop
Logs
/var/log/apache2
PHP
php ini
/etc/php5/apache2/php.ini
Sessions temp dir
/var/lib/php5
Pear and all of that stuff
/usr/share/php5
mysql
config file (my.cnf)
/etc/mysql/my.cnf
Delete tables with a certain pattern (drop tables like)
mysql --user=theuser --password=thepassword -N -e "show tables like 'whatever%'" db_name | perl -e 'while(<>){chomp; push @tables, $_;}print "drop table " . join ("," ,@tables) . "\n";' | mysql --user=theuser --password=thepassword db_name
Restore a dump
mysql -u username -p databasename < dump.sql
It will ask you for that username password
Files
Find files which have been modified today
find. -mtime -1 -print
Find all backup files in a directory
find. -name *~ -print
Find all backup files and delete them!
find. -name "*~" -exec rm {} \;
Change permissions for all folders only
find. -type d -exec chmod g+x {} \;
Set the group id bit (so files created later in the folder belong to the folder’s group)
chmodg+s directory
Uncompress lots of zips with just one line of terminal commands
find*.zip -exec unzip {} \;
Find only files
find. -type f
Find only files … and delete them!
find. -type f -delete
Recursively find files which contain a given text
grep-lir "a given text" *
Available space in disk
df-h
(in fact this return available space in each mount in the system)
Show differences between two files without taking into account whitespace (very useful when line returns and spaces/tabs are messing up normal diffs)
diff-w file1 file2
Get the md5 hash of a file
md5sum filename
Sharing folders
Right click over the folder to share, select ‘Sharing options’, click ‘Share this folder’ and ‘Allow other people to write in this folder’. For setting the samba user and password, open a terminal and run
sudo smbpasswd -a username
, where username is the username you’ll use when asked by Samba. The password you’ll set is the one you want to use for accessing that folder remotely. It does not need to be your system password. This way when you do changes in the folder, the changes are done by username, not by nobody.
Backups
archive and compress a whole directory
tarcvfz archive.tar.gz dname
backup a database
mysqldump db_name --user=username --password=password > database_dump.sql
backup all databases
mysqldump -u username -p --all-databases >/tmp/databases.dump
All-in-one: get a remote database dump, compress it, download and uncompress in your local machine
sshyour_host "cd dumps_dir; mysqldump --user your_user --password=your_pass --host=db_host database_name | gzip > database_name.gz"
scp your_login@your_host:dumps_dir/database_name.gz ./sql/
gunzip ./sql/database_name.gz
Compress a file with zip
zipoutputfile.zip file1 file2 file3... fileN
Download a remote directory to current directory
scp-rv yourlogin@yourhost:~/web/public_html .
Archive a directory in several files of 1Gb each
tarvcf - /path/to/dir | split --bytes=1024m -a 3 -d - output_prefix
And to join them and unarchive at the same time:
cat/path/to/archived_files/output_prefix* | tar xvf
Mounting internal drives
Let’s say I want to create a mount point for a secondary backup disk, so that it is always mounted without having to do it manually each time I want to use it.
Find out name of disk/partition
sudo fdisk -l
For example, /dev/sdb1 is the partition I want to mount. It can be different for you
Create mounting point
sudo mkdir /backup
Find UUID of the partition to mount
sudo vol_id /dev/sdb1
It returns both the filesystem type (ext3 in this case) and the UUID:
ID_FS_USAGE=filesystem
ID_FS_TYPE=ext3
ID_FS_VERSION=1.0
ID_FS_UUID=4ae128f5-b8a5-46ca-a27b-ddc03af18171
Edit /etc/fstab file to include the new partition in the list of mounts
Add a line like UUID={UUID} /{mount_point} {fs_type} defaults 0 0. Inmy case:
UUID=4ae128f5-b8a5-46ca-a27b-ddc03af18171 /backup ext3 defaults 0 2
Note that the last ’2′ is for telling fsck that it should check this disk after it checked the first one (which is the root one and should have an ’1′ instead of ’2′). If you enter a ’0′ this partition will never be checked when starting the system; that’s probably not a good idea.
Did we do it right? Try to refresh the mounts with this:
sudo mount -a
If there are no errors, you should be able to access the new mount point with the File Browser. If you get something like mount: special device 4ae128f5-b8a5-46ca-a27b-ddc03af18171 does not exist you probably forgot to add UUID= before the actual UUID, like I did :D
Give proper permissions – normal users can’t write in the new mount because it belongs to root.
In my case:
sudo chown -R sole:sole /backup
sudo chmod -R 755 /backup
These can take a long time — specially if there are lots of files in the disk and it is large :)
Note: mostly taken from this fab tutorial
Updates
Remove unused packages
sudo apt-get autoremove
Manually update greyed out entries in the update manager
Go to Synaptic Package Manager, order by the status column (i.e. the first one), select all the packages with a star (*) over a green background, and select “Mark for upload”.
Distribution update
sudo apt-get dist-upgrade
sudo gksu “update-manager -c”
Crisis!! X server doesn’t work after updating the distribution – boot in safe mode and run
sudo apt-get install –reinstall xserver-xorg
sudo dpkg -reconfigure xserver-xorg
System
Turn off
sudo shutdown
Reboot
sudo reboot
List mounted devices and disks and other info
sudo fdisk -l
Static file system information
/etc/fstab
Fcsk – boot from live CD (it won’t allow you to fsck a mounted drive)
open a console with ctrl+alt+f1
then sudo fsck /dev/sdb, etc
Another option: sudo e2fsck -p -f -v /dev/sda
Force fsck on boot
sudo touch /forcefsck and reboot!
Change screen resolution using command line
xrandr -s new_widthxnew_height
example: xrandr -s 1920×1200
Xorg
Restart xorg
press ctrl+alt+backspace
Net stuff
Download a file with curl
curl -o outputfile source_url
Mirror a website with wget
wget -m http://example.com
Or wget -H -r –level=2 -k -p http://examples.com to download files up to 2 levels recursively
Simulate different bandwidth speeds for testing your site (aka Bandwidth Throttling)
trickle -u 10 -d 20 firefox
Thanks to mr.doobfor this one!
Subversion
List info for a remote repository
svn info svn://repository_url (or http://repository_url, etc)
svn info also works with local resources: svn info . lists info for current directory
List files in a repository path
svn list svn://repository/path
Relocate a server location
svn switch –relocate svn://svnserver svn://svnserver/yellow_dog (taken from here)
Fire up svn server daemon
svnserve -d -r /home/svn/path_to_repositories_root
VirtualBox
Recompiling kernel module after upgrading the kernel:
sudo aptitude install linux-headers-$(uname -r)
sudo /etc/init.d/vboxdrv setup
Some people suggest using “sudo aptitude install virtualbox-ose-modules-generic” which is “a metapackage”. I haven’t tested it.
PulseAudio
Stop and restart
pkill pulseaudio; pulseaudio &
PGP & co
Clearsigna file with a non-default key
gpg –default-key [KEYID] –clearsign [FILENAME]
