Free derivatives of Unix can be easily downloaded via the Internet. This sets Unix apart from other proprietary operating systems like Microsoft Windows. The different Unix versions and Unix-like operating systems available for download include FreeBSD, OpenBSD, Red Hat Fedora Linux, Debian Linux, Ubuntu Linux, and Sun Solaris. Those who are new to Unix or …
The total number of Unix commands is immense. No normal user or system administrator would ever need to know them all. The Unix commands available to you will vary based upon several factors: The version of Unix you are using (FreeBSD, Linux, Solaris, AIX, HP-UX, OpenBSD, etc…) The Unix shell you are using (sh, csh, …
Keeping track of your CPU’s performance is extremely important. In UNIX, you can accomplish this task by using the system utilities and commands. For those who would like to find out their CPU utilization, one command is extremely important. It is called SAR – System Activity Reporter. The SAR commands make accessing CPU performance quite …
One way that a small business that requires a file server can save thousands of dollars per year is to set up a Linux file server. Linux is an open source software platform that, in many ways, is just as good as or better than other types of platforms including Microsoft and Sun. Small businesses …
CAD programs can be an exciting and helpful tool when designing blueprints for a house, vehicle, or electrical circuit. One of these programs is the popular LinuxCAD software that allows you to edit and create a number of blueprints and schematics under the Linux operating system. LinuxCAD comes with many features that other CAD programs …
A signal is a message that can be sent to a running process. Programs, users, or administrators can initiate signals. For example, the proper method of telling the Internet Daemon (inetd) to re-read its configuration file is to send it a SIGHUP signal. For example, if the current process ID (PID) of inetd is 4140, …
Unix users write, edit, list, and remove cron jobs using the `crontab` command. `crontab -e` takes users into their default editor to edit their crontab entries. `crontab -l` lists their crontab. `crontab -r` removes their crontab. crontab Security If the cron.allow file exists, then the user must be listed in that file in order to …
List Logged In Unix Users Unix has many commands to list users who are logged in. These commands include ‘w,’ ‘who,’ and ‘users:’ $ w 9:51PM up 99 days, 5:39, 2 users, load averages: 0.83, 0.90, 0.90 USER TTY FROM LOGIN@ IDLE WHAT will p0 c-66-164-235-73. 8:11AM – w spencer p3 c-66-164-235-73. 8:26PM 1:24 pine …
Tar refers to a tape archiving file format and the program that creates them. Tar stands for tape archive. It combines multiple files together so that they can be used for programs, applications, and critical system files. While Tar does not directly install files to a user’s hard drive, it is responsible for compiling the …
The idea of a restricted shell first arose in the Unix operating system in order to prevent the end-user from doing as many operations as a normal shell allows. A restricted shell lets the administrator control the end-user’s computing environment by only permitting explicitly used commands to be used. The Linux restricted shell (rssh) is …