Wednesday, August 24, 2016

tar: Archives cheatsheet

Create archive:
tar -czvf compressed_file.tar.gz original_file.sql
Extract files:
tar -xzvf compressed_file.tar.gz

Tuesday, August 2, 2016

Number of connections to the specific port

To check how many connections are exists to the port 3306:
watch -n 1 "sudo netstat -anp | grep 3306 | wc -l"

Monday, June 27, 2016

fedora: Increase watches limit

Open configuration file:
sudo vim /usr/lib/sysctl.d/50-default.conf
Add the following line to the end of the file to increase watches limit:
fs.inotify.max_user_watches = 524288

Saturday, June 25, 2016

postgresql: How to fix ERROR: new encoding (UTF8) is incompatible

Sometimes I'm unable to create a database in UTF8 encoding because the template database is in the ASCII encoding. To fix it we need to recreate template database in UTF8. Start psql console:
psql -U postgres
Run the following commands:
UPDATE pg_database SET datistemplate = FALSE WHERE datname = 'template1';
DROP DATABASE template1;
UPDATE pg_database SET datistemplate = TRUE WHERE datname = 'template1';
\c template1

Tuesday, May 31, 2016

Preview docs

It is possible to preview apiary docs before pushing to the repository. To do that, install apiaryio CLI:
gem install apiaryio
The executable file of the installed application is located somewhere there:
Generate html file to preview docs and open it in the browser:
/home/jsn/.gem/ruby/gems/apiaryio-0.3.3/bin/apiary preview --output="preview.html"

Friday, May 13, 2016

fedora: Install HipChat 4

UPDATED: Atlassian team has a rpm repository which they do not mention on the official download page. To install hipchat4 from it, create a repository file:
sudo gedit /etc/yum.repos.d/hipchat4.repo
With the following content:
name=Atlassian Hipchat4
Install hipchat:
sudo dnf install hipchat4 --refresh
Atlassian team wasn't able to release rpm package for the latest hipchat for more than 2 months. Fortunately, it is possible to intsall hipchat from the debian package. Download the latest available debian package from here.

Install alien package which will convert deb package to the rpm package:
sudo dnf install alien
Convert hipchat debian package to rpm package:
sudo alien HipChat4-4.0.1635-Linux.deb -r
Install hipchat:
sudo dnf install hipchat4-4.0.1635-2.x86_64.rpm

fedora: X11 forwarding issue

Here I have a nice post how to open browser window on the remote machine. On fedora 23 that method stopped to work. It was possible to start simple application like xclock, but firefox or chrome.
The problem is in the xorg-x11-drv-intel package. The latest version which is available in the official fedora repo is xorg-x11-drv-intel-2.99.917-19.20151206.fc23 (as for 13 May 2016). Downgrading the package to the previous version fixes the issue.
The latest version of the package which is known to work is xorg-x11-drv-intel-2.99.917-19.20151206.fc23. Let's install it:
sudo dnf install xorg-x11-drv-intel-2.99.917-16.20150729.fc23.x86_64
It would be also nice to lock the package version, so the next time you start updating the system it won't be updated:
sudo dnf install 'dnf-command(versionlock)'
sudo dnf versionlock add xorg-x11-drv-intel