To check the version of Samba that you are running, use the smbstatus command. The first line is the version, which should look something like:
Samba version 3.6.3
If you want to see just the version without the rest of the smbstatus information, you can run:
smbstatus –version
Much less cluttered. The above is the current version for a 12.04 Ubuntu server. Still waiting for version 4!
Was asked to troubleshoot a client’s installation technique for WordPress on CentOS 6.x yesterday; they were receiving an Error 500 when they tried to access index.php for the first time. Checking the Apache logs showed:
SoftException in Application.cpp:431: Mismatch between target GID (522) and GID (65531) of file “/home/andrea/public_html/index.php”
Premature end of script headers: index.php
What was happening was that the client was un-tarballing the latest.tar.gz file as root and then changing the ownership of the file with the following:
chown -R [user] *
Changing that command to:
chown -R [user]:[usergroup] *
e.g. here:
chown -R andrea:andrea *
fixed that error. By not specifying the new group there was an ownership mismatch where the system expected one group but got another. There are many causes for an Error 500 – it’s a good habit to check the Apache logs first for pointers as to where to start troubleshooting.
Rather than being in /var/log as you might expect, the Apache logs can be found at:
/etc/httpd/logs
Here you’ll find the usual access, error etc. logs.
If you’re looking to make a copy of a user’s crontab as a backup or just to view it without using the crontab editor, you can locate it at:
/var/spool/cron/crontabs
Each user’s crontab will be in this directory in a file named as their username (e.g. root). If you’re working with a lengthy crontab it’s a good idea to back it up – can save you a lot of work if everything goes pear-shaped.
This is a tricky one to find, mainly because by default it doesn’t exist. You create your custom configuration file in your home directory in a hidden file like so:
~/.tmux.conf
…and add your desired configuration changes to that file. So, if you were the user bob, your config file would be located at:
/home/bob/.tmux.conf
Since it is a hidden file (prefixed with a period) you won’t see it on ls – you need to use:
ls -al
(or ls -a if you don’t like lists) to see it in the directory.
Saw this on a new Mediawiki install where all of the optional extensions were selected, LocalSettings.php had been uploaded to the server and that’s as far as it would go.
To fix, open up LocalSettings.php and comment out the line:
require_once( “$IP/extensions/LocalisationUpdate/LocalisationUpdate.php” );
You should now be able to refresh the main page and start using your wiki.
One of the many useful options rsync offers is the ability to do a dry-run – in effect showing you what it would do without actually making any changes. To achive this we use the -n flag, like so:
rsync -n /source /destination
In practice we would likely use the -n switch in combination with other switches – commonly we use -avzP, so our real-world example would look like this:
rsync -avzP -n /source /destination
Thanks to the verbose flag (-v) you should see a full list of all of the files which would be transferred, as well as the final note on the last two lines:
sent 26457 bytes received 2086 bytes 19028.67 bytes/sec
total size is 26377806232 speedup is 924142.74 (DRY RUN)
…letting you know that it was a dry run and that no files were transferred.
This is just like extracting a regular tar archive:
tar -xvf /dev/[path to tape] [directory or file to restore]
e.g.:
tar -xvf /dev/st0 backups
This will restore the “backups” file/folder to the current working directory. To check your current directory, you can use:
pwd
to make sure that you are restoring your files to the correct location!
To check the contents of a tape, insert the tape and run the following:
tar -tf /dev/[path to tape device]
e.g.:
tar -tf /dev/st0
Note that typically it’s a zero, not a letter o, at the end.
To put files onto a tape, run the following:
tar -cvf /dev/[path to tape] [file or directory] [file or directory] [file or directory]
An example would be:
tar -cvf /dev/st0 /home/bob
This will back up the user bob’s home directory to the tape, here located at /dev/st0 (a typical location – note the zero, not the letter o).
If you want to use compression in your backup, use the z flag in addition to the other tar flags, such as:
tar -cvfz /dev/st0 /home/bob
All done!