Category: Administration

Everything related to system administration.

PHP reading problem with files larger than 2 GB

If you’ll ever have problem with opening (fopen) and reading (fread) files larger than 2 GB in your PHP script. Check your version of scripting engine. In my case switching to 64 bit solved the problem. Please mind that this error is very hard to debug because PHP does not log anything (same as MS IIS) in such case. It simply resets client connection…

Cryptic error 0x1 in Windows™ Task Scheduler

In case you ever wondered why your task returns 0x1 in Last Run Result instead of 0x0. Check if your task is trying to create any files, if it does, you must tick “Run with highest privileges” in General tab of your task properties. I’ve spent some precious time to uncover that because I’m not a native Winblows administrator 🙂

How to list all PostgreSQL databases and their sizes in MB

You must provide proper database name and user:


File: gistfile1.txt
-------------------

psql -c "SELECT pg_database.datname, pg_database_size(pg_database.datname), pg_size_pretty(pg_database_size(pg_database.datname)) FROM pg_database ORDER BY pg_database_size DESC;" -d

How to find Raspberry Pi using MAC address

When you want to find your headless but networked Raspberry Pi and you’re lazy like me use nmap:

sudo nmap -sP 192.168.1.0/24 | awk '/^Nmap/{ip=$NF}/B8:27:EB/{print ip}'

Mask /24 means that addresses from 192.168.1.0 to 192.168.1.254 will be searched. You can extend that to /16 if you don’t know subnet of your device.

Permission denied when script is trying to execute ps_files_cleanup_dir

This is pretty common problem. I’ve encountered it on recent version of the Debian operating system. When you see something like that:

Notice:  session_start(): ps_files_cleanup_dir: opendir(/var/lib/php5/sessions) failed: Permission denied (13) in /mnt/www-data/htdocs/raportMNW/inc/bryanjhv/slim-session/src/Slim/Middleware/Session.php on line 110

You can fix that easily with following Linux commands:

sudo nano /etc/php5/apache2/php.ini

Now use CTRL+W to find following string session.save_path and configure it like that:

session.save_path = "/tmp"

Save your file using CTRL+X and restart Apache2 service:

sudo service apache2 restart

And voilà!

How to change computer name remotely using Windows 7?

There is a command line tool called netdom. Unfortunately it’s not preinstalled on Windows 7. This guide will show how to add this tool to your system and how to change remote computer name.

Continue reading How to change computer name remotely using Windows 7?