Review

EssayQuestions

Processes

  1. What is a process?

Aprocess is an undertaking or a task that is at present running on asystem

  1. Describe environment components during execution.

  1. The program name is the command language that provides access to systems including Unix [Unix kernel] system on the many computers in which they are connected and is where the user logins into

  1. User ID-the Unix kernel gives the user a unique number when one is creating an account

  1. PROCESS ID-this a random number that unix kernel assigns to the program currently running

  1. GROUP ID –every user belongs to a certain group and this is the unique group number that a user belongs to

Afile is opened for each process and is the terminal where the userlogins. the logical name of the terminal is /dev/pts/1

  1. Parent – children relationship: how they affect each other

Aparent process affects its children but a child process does notaffect its parent.

Changesmade to a variable in the child process do not change the variable ofits parent even when being exported

Exportingonly works from a parent to a child, and not vice versa.

  1. Can a child process change variables in the environment of the parent processes?

No

  1. How to make shell variables global (environmental)?

They canbe made global by exporting them by using the export command

  1. What is a shell script?

Acomputer program contains commands stored in a text file thatperforms operation such as file manipulation. Program execution andprinting text

  1. Three ways of executing a script:

  1. Calling the script in a subshell without making it executable

  2. Making the script executable and calling it by its name for it tobe executed

  3. Using the [dot] which allows the script to run in the current shell

  1. What are return codes from commands execution?

They arevalues returned by a command to the parent process

  1. Process monitoring commands.

Theyare programs that check on the processes we run

  1. Terminating processes commands:

    1. For foreground processes

Terminatedby crtl+c or kill

    1. For background processes

Onlyterminated by kill

  1. Commands for job control in the Korn shell are:

  • Ctrl+z

  • Jobs

  • Fg

  • Bg

  1. The strongest signal to kill a process is: kill%1

  2. What are daemons?

Computerprograms in multitasking computer systems that never stops and runsas background processes