Linux – Listing and Manipulating Processes

A process is a running program. Each process on the system has a numeric process ID (PID). For a quick listing of running processes, just run ps on the command line. You should get a list like this one: $ ps PID TTY STAT TIME COMMAND 520 p0 S 0:00 -bash 545 ? S 3:59

Linux – Understanding Error Messages

Anatomy of a UNIX Error Message Most Unix programs generate and report the same basic error messages, but there can be subtle differences between the output of any two programs. Here’s an example that you’ll certainly encounter in some form or other: $ ls /dsafsda ls: cannot access /dsafsda: No such file or directory There

Linux – The big picture

Levels and Layers  of  Abstraction  in  a  Linux  System Hardware:  Understanding Main Memory This is where the running kernel and processes reside—they’re just big collections of bits. The Kernel – One of the kernel’s tasks is to split memory into many subdivisions, and it must always maintain certain state information about those subdivisions. Each process

Linux – Basic Commands

echo $ echo Hello there cat $ cat /etc/passwd  displays the contents of the  /etc/passwd  system information file and then returns your shell prompt $ cat file1 file2 … cat prints the contents of file1, file2, and any other files that you specify (denoted by  …), and then exits. Standard Input and Standard Output Unix

Linux – Shell Input and Output

Shell  Input  and  Output To send the output of command to a file instead of the terminal, use the > redirection character: $ command > file The shell creates file if it does not already exist. If file exists, the shell erases (clobbers) the original file first. (Some shells have parameters that prevent clobbering. For