This small guide may come handy…
From the article:
One great thing about Linux is that you can transplant a hard disk from a machine that runs a 32-bit AMD XP processor into a new 64-bit Intel Core 2 machine, and the Linux installation will continue to work. However, if you do this, you’ll be running a 32-bit kernel, a C library, and a complete system install on a processor that could happily run 64-bit code. You’ll waste even more resources if your new machine has 4GB or more of system memory, and you’ll be forced to either not use some of it or run a 32-bit Physical Address Extension (PAE) kernel. Cross-grading to the 64-bit variant of your Linux distribution can help you use your resources more wisely. A disclaimer: changing the architecture of your Fedora installation from 32 to 64-bit isn’t recommended or supported in any way. Perform this at your own risk after creating a suitable backup.
=> Upgrade from 32-bit to 64-bit Fedora Linux without a system reinstall [linux.com]
Generally service such as ssh, screen, expect, telnet etc use pty (pseudo-terminals) in master – slave mode for login and other purposes. If pty setting is too low many users will not able to login to system using ssh or other commands. In this tip I will explain how to increase the maximum number of pseudo-terminals.
pty man page defines pseudo-terminal as follows:
A pseudo-terminal is a pair of virtual character devices that provide a bidirectional communication channel. One end of the channel is called the master; the other end is called the slave. The slave end of the pseudo-terminal provides an interface that behaves exactly like a classical terminal. A process that expects to be connected to a terminal, can open the slave end of a pseudo-terminal and then be driven by a program that has opened the master end. Anything that is written on the master end is provided to the process on the slave end as though it was input typed on a terminal.
List the maximum number of Pseudo-terminals
Just run the following command to list / display the maximum number of Pseudo-terminals under Linux
$ cat /proc/sys/kernel/pty/max
Increase the maximum number of Pseudo-terminals (PTY)
If you have large Linux installation such as University or ISP login service you need to increase the PTYs to allow more login sessions. Open kernel configuration file – /etc/sysctl.conf:
# vi /etc/sysctl.conf
Append following config directive (support 5120 ptys)
kernel.pty.max = 5120
Save and close the file. Reload the changes:
# sysctl -p
Verify that the new maximum number of pseudo-terminals value is changed, enter:
$ cat /proc/sys/kernel/pty/max
=> Refer to sysctl, proc, and pty man pages for more information.
Sure you can use unzip, unrar, and other tools to extract files under Linux. e is little tool that can extract almost any archive in Linux so you do not need to remember which tool and what command lines are necessary.
You need ruby lanaguage installed on your computer to use this tiny tool. Apart from Ruby, e uses the linux tool file to determine what kind of archive it is dealing with. This tool should be available on any proper Linux installation. Once e knows the archive type, the appropriate extraction tool is executed.
You can read more about this tool, installation and other notes at Martin Ankerl blog.
One of our regular reader hall sends an interesting question:
I work for a small company and most user login to centralized Linux server. I’d like to
automatically log out all inactive users from server for various reasons. How do I disconnect inactive user sessions?
To be frank, I don’t have any clear cut answer to question. There are at least 4-5 shells installed on a typical Linux installation. Also most user have has control over their own environment and user can switch to a different shell.
I hope our reader or seasoned UNIX admin can help to answer this question. Please share the experiences and advice in the comments.
Update: Checkout answer below in comments!