Difference between revisions of "Introduction to Linux in HPC/Users and permissions"
Introduction to Linux in HPC/Users and permissions
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(Created page with "__TOC__ === Video === <!--T:5--> <youtube width="600" height="400" right>IfD9IPixgpo</youtube> [https://git-ce.rwth-aachen.de/hpc.nrw/ap2/tutorials/linux/-/blob/master/Slid...") |
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Single-letter commands for top | Single-letter commands for top | ||
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| + | === Quiz === <!--T:5--> | ||
| + | |||
| + | |||
| + | {{hidden begin | ||
| + | |title = Which command can prevent other users not in your group from writing to input.dat? | ||
| + | }} | ||
| + | <quiz display=simple> | ||
| + | { | ||
| + | |type="()"} | ||
| + | - chmod u-w input.dat | ||
| + | || | ||
| + | + chmod o-w input.dat | ||
| + | || Explanation: The chmod command changes file permission. u represents the user who owns the file. g means other users in your group and o stands for other users not in your group. -w means to remove the write permission. Therefore B is the correct answer. | ||
| + | - chmod g-w input.dat | ||
| + | || | ||
| + | </quiz> | ||
| + | {{hidden end}} | ||
Revision as of 18:21, 1 October 2020
Video
Linux Introduction Slides 67 - 88 (22 pages)
Slide Layout
page 1:
Linux is a multi-user system.
A user is logged in with an account and certain permissions.
page 2:
Each file and directory has certain permissions.
root has top permissions.
Normal users may belong to multiple groups.
page 3:
Read permission
Write permission
Execute permission for i) file and ii) directory
page 4 - 12:
Example of ls -l (animation)
page 13 - 16:
Permissions for user, group and other (animation)
page 17:
chown to modify owner/group
chmod to modify permission
page 18:
Process is an instance of a program
top and pstree
Each process has permissions of that user.
Each process has a unique ID (PID).
page 19:
Start command in background command &.
Ctrl-Z and bg
fg brings a job to foreground.
page 20 - 21:
Example of top (animation)
page 22:
Single-letter commands for top
Quiz
Which command can prevent other users not in your group from writing to input.dat?