Answer and try out. File permissions Say you have a file called "myfile.txt". Write the command to make it readable and writable by the owner, but only readable by everyone else. You have a shell script named "backup.sh". Write the command to make it executable by the owner only. There's a file …

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Using basic commands Answer and try out: What command would you use to display your current location in the file system? Which command shows the list of files and directories in your current location? What command would you use to create a new directory called "projects"? Which command allows you to change …

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Here are some usefull linux links: Virtualization Tools VmWare Workstation/Fusion (free for personal use) VmWare is now owned by Broadcom You'll have to create a Broadcom account (free) main link Linux Images or prepared disks Easiest if you have Windows/Workstation: Download a complete ready vmdk file from osboxes ( …

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About vi vi is a screen-oriented text editor originally created for the Unix operating system vi was a visual mode of the ex line editor, hence the name Being screen-oriented means that vi would work in a terminal you would use to connect textually to UNIX like systems (so telnet and ssh would be enough to use it) The …

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Let's create our own systemd service. Our service program We'll use a simple bash script that endlessly outputs text into a log file: 1for (( ; ; )) 2do 3 echo "still running:" $(date) >> /tmp/myprog.log 4 sleep 1 5done Save this in a file, make it executable by anyone (777) and copy to /usr/bin: Service …

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About systemd Units Units are the objects that systemd knows how to manage. These are basically a standardized representation of system resources that can be managed by systemd Each unit is configured by a unit file Here's are some of systemd units: .service: A service unit describes how to manage a service or …

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About systemd systemd is a software suite that provides an array of system components for linux The primary component is a "system and service manager" – an init system used to bootstrap user space and manage user processes. It also provides replacements for various daemons and utilities, including: device …

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About System Calls Some operations that are executed by a process involve just the CPU and the memory. Mathematical computations and logical decisiones are good examples of these. But sometimes, the process needs to do other things, that it cannot do alone. For example: interract with the computer hardware (e.g hard …

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Traditional creation of programs This is also called static linking The old way of creating programs was by writing multiple source files (text files with program code), then translating each one (called compile), thus creating object files. The, link these files to create an executable file, that can be run: Dynamic …

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What is a process A process is an instance of an executing program. A program is a file containing a range of information that describes how to construct a process at run time: Machine-language instructions: These encode the algorithm of the program. Data: The program file contains values used to initialize variables …

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