Category Archives: Linux

Statically compile redis 3.0.2 on CentOS 5 (RHEL 5)

How to, Linux, Programming, , , ,

How to statically compile redis 3.0.2 on CentOS 5 (RHEL 5)

wget http://download.redis.io/releases/redis-3.0.2.tar.gz
wget http://prdownloads.sourceforge.net/tcl/tcl8.5.18-src.tar.gz

Install tcl8.5

tar xfz tcl8.5.18-src.tar.gz
cd tcl8.5.18/unix
./configure
make
make test
make install

Compile redis

Statically linked binaries

make CFLAGS="-static" EXEEXT="-static" LDFLAGS="-I/usr/local/include/"

Dynamically linked binaries

make LDFLAGS="-I/usr/local/include/"

How to manually install redis

cd src/
cp redis-{server,cli} /usr/local/bin/
chown root: /usr/local/bin/redis-{server,cli}
chmod 755 /usr/local/bin/redis-{server,cli}
mkdir /{var,etc}/redis /var/redis/6379
chmod 775 /{var,etc}/redis
cp redis.conf /etc/redis/6379.conf
sed -i 's/daemonize no/daemonize yes/' /etc/redis/6379.conf
sed -i 's,pidfile /var/run/redis.pid,pidfile /var/run/redis_6379.pid,' /etc/redis/6379.conf
sed -i 's/^# bind 127.0.0.1/bind 127.0.0.1/' /etc/redis/6379.conf
sed -i 's,logfile "",logfile "/var/log/redis_6379.log",' /etc/redis/6379.conf
sed -i 's,dir ./,dir /var/redis/6379,' /etc/redis/6379.conf

Useful aptitude commands

Linux, , , , , ,

A simple list of installed packages

max@wonko:~$ aptitude search '~i' -F '%p'

Search for installed packages from the testing repo

max@wonko:~$ aptitude versions '~i ~Atesting' --group-by=none

Finding why a package is installed

I found fonts-font-awesome in my headless server, but there’s a reason

max@wonko:~$ aptitude why fonts-font-awesome
i   owncloud Depends fonts-font-awesome

Select packages that were removed but not purged

max@wonko:~$ aptitude search '~c'

Search in the package description

max@wonko:~$ aptitude search '~d"web browser"'

Upgradable packages

max@wonko:~$ aptitude search '~U'

How to compile rsync for Android in Ubuntu

Android, How to, Linux, Programming, , , , , , , ,

My situation

My machine

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04 LTS
Release:    14.04
Codename:   trusty

The latest rsync version to compile (for me it was rsync-3.1.0.tar.gz)

$ curl -s http://rsync.samba.org/ftp/rsync/ \
    | sed -r 's/^.*href="([^"]*)".*$/\1/' | grep 'rsync-[0-9].*\.tar\.gz$'

Procedure

  1. save the tarball name in a variable 
    $ RSYNCTGZ="rsync-3.1.0.tar.gz"
  2. install needed software 
    $ sudo aptitude install gcc-arm-linux-gnueabi
  3. download sources 
    $ wget http://rsync.samba.org/ftp/rsync/$RSYNCTGZ
$ tar xzf $RSYNCTGZ
$ cd rsync-[0-9]*
  4. compile 
    $ ./configure --host=arm-linux-gnueabi CFLAGS=-static
$ make
  5. install on the device 
    $ adb push rsync /data/local/tmp && adb shell chmod 775 /data/local/tmp/rsync
  6. test execution 
    $ adb shell /data/local/tmp/rsync

References

How to display PHP errors only in public_html directories

How to, Linux, Programming, Uncategorized, web, , , , , , , , , ,

How to display PHP errors

I always use servers where PHP errors are not shown by default and I always forget how to enable error messages in development environments.

My situation

On a server I usually prefer Debian OS, but when I develop on the go I use laptops with Ubuntu.
In this case I’m running Ubuntu 14.04 LTS with Apache2 (v2.4.7) and libapache2-mod-php5 (v5.5.9).

I want PHP errorors displayed for projects in my public_html folder.

Solution 1 (only Apache conf files)

Create the file /etc/apache2/sites-enabled/800-public-html.conf with this content:

<Directory /home/*/public_html>
  AllowOverride Options
  php_admin_flag display_errors On
</Directory>

Solution 2 (using .htaccess)

Create the file /etc/apache2/sites-enabled/800-public-html.conf with this content:

<Directory /home/*/public_html>
  AllowOverride Options
</Directory>

Create the file /home/max/public_html/project1/.htaccess with this content:

php_admin_flag display_errors On

Conclusions

It’s easy and easily forgettable. Don’t forget to add

error_reporting(E_ALL | E_NOTICE);

in your .php files.

Restore an etc configuration file from the original maintainer version on Debian

How to, Linux, , , , , , , ,
There are events that can not be stopped, for example when you delete a file by mistake under /etc.

Debian provides an elegant way to restore files of the maintainer’s version without touching your existing configuration.

Practical scenario

Let’s say I’ve removed the file /etc/apache2/sites-available/000-default.conf, here’s the procedure to recover it:

  • find the deb package containing the file 
    # dpkg -S /etc/apache2/sites-available/000-default.conf
  • reinstall the package with a specific option 
    # apt-get install --reinstall -o Dpkg::Options::="--force-confmiss" apache2
Reading package lists... Done
Building dependency tree       
Reading state information... Done
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 5 not upgraded.
Need to get 86,7 kB of archives.
After this operation, 0 B of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu/ saucy-updates/main apache2 amd64 2.4.6-2ubuntu2.1 [86,7 kB]
Fetched 86,7 kB in 0s (264 kB/s)
(Reading database ... 245864 files and directories currently installed.)
Preparing to replace apache2 2.4.6-2ubuntu2.1 (using .../apache2_2.4.6-2ubuntu2.1_amd64.deb) ...
Unpacking replacement apache2 ...
Processing triggers for man-db ...
Processing triggers for ufw ...
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot
Setting up apache2 (2.4.6-2ubuntu2.1) ...

Configuration file `/etc/apache2/sites-available/000-default.conf', does not exist on system.
Installing new config file as you requested.
 * Restarting web server apache2
   ...done.

That’s all.

Practical scenario #2

There’s another interesting case when this procedure comes handy: if you changed a default etc file and you want to restore it. In that case you can simply delete it and use the same apt-get command:

# apt-get install --reinstall -o Dpkg::Options::="--force-confmiss" <package name>

References