Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
What are its advantages in Ext4?
Answer:
See the complete lists of benefits here: http://en.wikipedia.org/wiki/Ext4#Features
One of the most important features is the called the delayed allocation.
Delayed allocation means delaying the block allocation process until the data is going to be written to the disk, which improves performance and reduces fragmentation.
Should I always use single-quotes for PHP strings?
Answer:
Some people say single-quotes string is faster than double-quotes string in PHP. But this have been rejected by the PHP's developer
Benchmarks run against PHP 5.2 and 5.3 show that parsing double-quoted
strings with interpolation is no slower (and often faster) than single-
quoted strings using concatenation. When simple strings with no
variables in them are used, the performance is clearly better with
double-quoted strings due to implementation details in the engine. See
the benchmark posted at . Reference: http://groups.google.com/group/make-the-web-faster/browse_thread/thread/ddfbe82dd80408cc?pli=1
How to check all the commands executed in a Linux server?
Answer:
The short answer is no.
But it might be possible by looking at the .bash_history under the user folder, but keep in mind that user can clear their history by using "history -c" command, or they can delete the file manually.
If you want to force logging on all user, what you need is called "process accounting".
See a more comprehensive howto: http://tldp.org/HOWTO/Process-Accounting/
How to compile APC module for PHP
Answer:
The following steps works in RHEL/CentOS
1. Download the latest APC from PECL
wget http://pecl.php.net/get/APC
2. Extract the APC source package and compile/install it
tar -xvf APC
cd APC-X.X.X (replace with your downloaded version)
phpize
./configure
make && make install
3. Enable APC in PHP configuration
echo "extension=apc.so" > /etc/php.d/apc.ini
4. Restart the httpd and use phpinfo() to verify if APC is running
Find out the CPU model in Linux
Answer:
You can find the CPU information at /proc/cpuinfo
# grep "model name" /proc/cpuinfo
model name : Intel(R) Core(TM)2 Quad CPU Q9400 @ 2.66GHz
