Newer versions of R(>=3.3.x) will not build without newer bzip2, zlib, libcurl & pcre. These dependencies are not available on older version of RHEL & CentOS i.e. anything below RHEL & CentOS 7. This blog post is a step-by-step journal of what I encountered when trying to compile & install R v3.3.2 on a CentOS 6 host.
At times I’d just like to run a script or a program without using my current or pre-existing shell environment variables. Running bash -l doesn’t really help because it just starts a new bash shell login with the same environment variables from your ~/.bashrc or profile.d system-wide settings. Well, the other day I discovered prefixing your program/script with env temporarily clears your environment variables so that your script just runs with totally no variables!
MySQL slow query log consists of SQL statements that took more than long_query_time seconds to complete execution & required atleast min_examined_row_limit to be examined. By default, administrative queries & those that don’t use indexes for lookups are not logged.
OpenPGP supports subkeys which are like the normal keys, except they’re bound to a master key pair. A subkey can be used for signing or for encryption. The really useful part of subkeys is that they can be revoked independently of the master keys, and also stored separately from them.
MySQL replication allows you to ‘mirror’ databases on one or more servers(master) to one or more servers(slave). You can control what to replicate such as one or more databases, or even tables within a database i.e. selective replication.