Tips and Tricks

Package management (Portage)

To which package belongs file X

# equery belongs -f <dateiname>

Which packages has USE-Flag X

# equery hasuse <useflag>

Backup an installed package

# quickpkg net-www/apache

After this you can install the package on another machine or do a fast downgrade if something went bad after an update. You can find the file under /usr/portage/packages/All and in this example a symlink to the apache file in /usr/portage/packages/net-www. To install the now precompiled binary use:

# emerge --usepkgonly "<net-www/apache-2.2.4"

Detect and get rid of leftover packages

# emerge depclean --pretend

Change your current profile

# emerge eselect

# eselect profile list

# eselect profile set <nummer>

Useful commands

Recursively set directory permissions to 755:

# find /var/www/path -type d -print0 | xargs -0 chmod -c 755

Character conversion

Recursively rename directory and files from ISO-8859-15 to UTF-8:

# convmv -f iso-8859-15 -t utf8 -r /var/www/path --preserve-mtimes --notest

SCP file transfer

File transfer via commandline.

Upload file:

# scp /root/htdocsbackup.tar.bz2 root@remote-host.de:/root/

Download file:

# scp root@remote-host.de:/root/htdocsbackup.tar.bz2 /root/htdocsbackup.tar.bz2

Upload directory:

# scp -p -r /root/directory root@remote-host.de:/root

Download directory:

# scp -p -r root@remote-host.de:/root/directory /root

SSH tunnel

Very useful if the server you want to connect to has only the SSH port open and/or a firewall infront and you want to access for example a tomcat server running on port 8080.

# ssh -N -i /home/<user>/.ssh/id_dsa -L 7777:remote-host.de:8080 root@remote-host.de

After establishing the tunnel you can access the tomcat server of the remote machine port 8080 at your localhost port 7777.

KDE4 problems and workarounds

Reset to the default Plasma layout

Log out of KDE/X and delete from tty:

$ rm ~/.kde/share/config/plasma*

Change the Dolphin standard view to detailed view for ALL folders

Open Dolphin -> Settings > Configure Dolphin -> Views -> Common Tab -> and mark -> Use the same view for all folders