Course 102: Lecture 3: Basic Concepts And Commands
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The document provides an overview of basic Linux commands and file management techniques for embedded systems. It covers naming conventions for files, directory structures, absolute and relative paths, and essential commands for listing, moving, copying, and deleting files and directories. The content serves as a foundational guide for understanding and working with Linux in an embedded environment.
![Commands
• General form of Commands,
$ <command> [options] [arguments]
• Commands can be issued on their own
$ ls
$ pwd
$ cd
• The Options are normally optional (by definition)
The usually start with ‘-’ or ‘--’
‘-’ used with the short name for the option
$ ls -a
‘--‘ used with the long name for the option
$ ls --all
We normally use the short name in CLI and the long name in scripts (for
clarity)](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-5-320.jpg)
![Listing Files
(ls Command)
$ ls [options] [<dir or file> ..]
$ ls (list current directory)
$ ls -a (all: show hidden files)
$ ls -l (long: show file details)
$ ls -t (timestamp: sort based on timestamp)
$ ls -S (Size: sort based on file size)
$ ls -r (reverse: make the sort in reverse order)
$ ls -d (directories: Only show directories)
$ ls -R (Recursive: list files inside subdirectories)
$ ls <dir> (List the contents of the mentioned directory)
$ ls <file> (List the mentioned)
$ ls <dir or file> <dir or file> <dir or file> (list selected dirs or files)
Or a Mix of These Options](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-12-320.jpg)
![Displaying the Directory Tree
(tree Command)
$ tree [options] [<dir or file> ..]
$ tree (display the full tree starting from current dir)
$ tree -d (only show directories)
$ tree -a (show all files; including hidden ones)
$ tree <dir> (show the tree starting from a different point)
Or a Mix of These Options](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-15-320.jpg)
![Moving Around
(cd Command)
$ cd [destination]
$ pwd
/home/bio1/](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-17-320.jpg)
![Moving Around
(cd Command)
$ cd [destination]
$ cd /usr/local](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-18-320.jpg)
![Moving Around
(cd Command)
$ cd [destination]
$ cd /usr/local/bin
$ cd ./bin
$ cd bin](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-19-320.jpg)
![Moving Around
(cd Command)
$ cd [destination]
$ cd /usr/etc
$ cd ../../etc](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-20-320.jpg)
![Moving Around
(cd Command)
$ cd [destination]
$ cd ~
$ cd](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-21-320.jpg)
![Moving Around
(cd Command)
$ cd [destination]
$ cd /etc/network (absolute path)
$ cd ../project/ (relative path)
$ cd ./project (relative path)
$ cd project (relative path, same as ./project)
$ cd ~ (go to my home directory /home/aelarabawy/)
$ cd ~user_name (go to /home/user_name)
$ cd (same as cd ~)
$ cd .. (go to parent directory)
$ cd - (go to previous directory)](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-22-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
file.cfgprog1prog2prog3
util1 util2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-42-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
file.cfgprog1prog2prog3
$ cd /usr/local/sbin
util1 util2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-43-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
file.cfgprog2prog3$ rm prog1
util1 util2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-44-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
prog2prog3$ rm ../etc/file.cfg
util1 util2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-45-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
prog2prog3$ cd ../bin
util1 util2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-46-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
util1 util2
$ rm prog3 prog2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-47-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
util1 util2
$ cd /usr/bin/utils](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-48-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
$ rm -r /usr/bin/utils
util1 util2](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-49-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
util1 util2
$ cd -](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-50-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
$ rm -r /usr/bin/utils](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-51-320.jpg)
![Removing files and Directories
(rm Command)
$ rm [options] <file or dir list>
$ rm file1 file2 (remove file1 and file2)
$ rm -r ../projects/folder1 (remove the folder with its content)
$ rm -i file1 file2 (interactive, ask me before you remove)
$ rm -f ../projects/folder1 (force, force remove)
• Note
• To remove directories you need always to use ‘-r’
• You can not remove your current directory (or any of its parents)](https://image.slidesharecdn.com/c102lec03basicconceptsandcommands-150521010659-lva1-app6891/85/Course-102-Lecture-3-Basic-Concepts-And-Commands-52-320.jpg)
Course 102: Lecture 3: Basic Concepts And Commands
- 1. Linux For Embedded Systems ForArabs Ahmed ElArabawy Course 102: UnderstandingLinux
- 2. Lecture 3: Basic Concepts and Commands
- 3. Files & Filenames • Filenames can use any characters abc??##.a1 sta*.pn But it is not wise to use special characters in filenames spaces are accepted but not recommended, use dashes or underscores instead test results.txt => test_results.txt or test-results.txt • File names are case sensitive Test_results.doc test_results.doc But avoid creating files with same names with difference in case • File names starting with a dot are hidden files .bashrc .profile • No concept of file extension, the dot is just another character file.txt.old .bashrc file.doc.mod .profile.old results.yesterday results Still it is a good idea to stick to the popular extensions for clarity
- 4. Paths • Directory names separated by slashes ‘/’ /usr/src/shared/files/myfile.txt • Can be absolute or relative • Absolute: Does not depend on where you are /home/aelarabawy/abcd ~/abcd ~ means /home/aelarabawy (home directory of current user) ~salah means /home/salah (home directory of the user salah) • Relative: Depends where you are in the tree ./my-project/progress-reports ../../my-project/progress-reports . means Current Directory .. Means Parent Directory
- 5. Commands • General form of Commands, $ <command> [options] [arguments] • Commands can be issued on their own $ ls $ pwd $ cd • The Options are normally optional (by definition) The usually start with ‘-’ or ‘--’ ‘-’ used with the short name for the option $ ls -a ‘--‘ used with the long name for the option $ ls --all We normally use the short name in CLI and the long name in scripts (for clarity)
- 6. Commands • If we want to use multiple options Sometimes we join options or keep them separate $ ls -a -R $ ls -aR $ ls --all --recursive • Sometimes a ‘--‘ without a name afterwards will mean end of options (even a following hyphen will not be considered a new option) • Arguments are those info passed to the command such as file names and paths $ rm -rf ./project-data
- 7. Basic Commands Command Effect $ ls To list files $ tree To list a tree of files $ pwd To show the current directory $ cd To move around in the tree $ mkdir To Create directories $ cp To copy files and directories $ mv To move or rename files and directories $ rm To delete files and directories $ clear To clear the screen
- 8. Listing Files (ls Command) $ ls (List Current Directory)
- 9. Listing Files (ls Command) $ ls -a (List all files, including hidden files)
- 10. Listing Files (ls Command) $ ls -l (List with long format)
- 11. Listing Files (ls Command) $ ls -l (List with long format)
- 12. Listing Files (ls Command) $ ls [options] [<dir or file> ..] $ ls (list current directory) $ ls -a (all: show hidden files) $ ls -l (long: show file details) $ ls -t (timestamp: sort based on timestamp) $ ls -S (Size: sort based on file size) $ ls -r (reverse: make the sort in reverse order) $ ls -d (directories: Only show directories) $ ls -R (Recursive: list files inside subdirectories) $ ls <dir> (List the contents of the mentioned directory) $ ls <file> (List the mentioned) $ ls <dir or file> <dir or file> <dir or file> (list selected dirs or files) Or a Mix of These Options
- 13. Displaying the Directory Tree (tree Command) $ tree (List tree from Current Directory)
- 14. Displaying the Directory Tree (tree Command) $ tree -a (List tree from Current Directory)
- 15. Displaying the Directory Tree (tree Command) $ tree [options] [<dir or file> ..] $ tree (display the full tree starting from current dir) $ tree -d (only show directories) $ tree -a (show all files; including hidden ones) $ tree <dir> (show the tree starting from a different point) Or a Mix of These Options
- 16. Print Working Directory (pwd Command) $ pwd $ pwd (Display Current Directory)
- 17. Moving Around (cd Command) $ cd [destination] $ pwd /home/bio1/
- 18. Moving Around (cd Command) $ cd [destination] $ cd /usr/local
- 19. Moving Around (cd Command) $ cd [destination] $ cd /usr/local/bin $ cd ./bin $ cd bin
- 20. Moving Around (cd Command) $ cd [destination] $ cd /usr/etc $ cd ../../etc
- 21. Moving Around (cd Command) $ cd [destination] $ cd ~ $ cd
- 22. Moving Around (cd Command) $ cd [destination] $ cd /etc/network (absolute path) $ cd ../project/ (relative path) $ cd ./project (relative path) $ cd project (relative path, same as ./project) $ cd ~ (go to my home directory /home/aelarabawy/) $ cd ~user_name (go to /home/user_name) $ cd (same as cd ~) $ cd .. (go to parent directory) $ cd - (go to previous directory)
- 23. Making New Directories (mkdir Command) $ mkdir <new directory name with path>
- 24. Making New Directories (mkdir Command) $ mkdir <new directory name with path> $ mkdir documents $ mkdir ./documents $ mkdir /home/tom/documents $ mkdir ~/documents
- 25. Making New Directories (mkdir Command) $ mkdir <new directory name with path> $ mkdir documents/text
- 26. Making New Directories (mkdir Command) $ mkdir <new directory name with path> $ cd documents $ mkdir text
- 27. Making New Directories (mkdir Command) $ mkdir <new directory name with path> $ mkdir documents/text
- 28. Making New Directories (mkdir Command) $ mkdir <new directory name with path> $ mkdir -p documents/text
- 29. Making New Directories (mkdir Command) $ mkdir <new directory name with path> $ mkdir project1 (create a new directory from current location) $ mkdir project1 project2 (create 2 directories) $ mkdir /home/aelarabawy/lectures (absolute path) $ mkdir ../projects/project1 (relative path) $ mkdir -p ../projects/project1 (create intermediate folders if needed)
- 30. Copying Files & Directories (cp Commands) $ cp <existing file or dir> <new filename & destination> science.doc
- 31. Copying Files & Directories (cp Commands) $ cp <existing file or dir> <new filename & destination> science.doc $ cp ~/books/science.doc ~/school/science.doc science.doc $ cp ~/books/science.doc ~/school/
- 32. Copying Files & Directories (cp Commands) $ cp <existing file or dir> <new filename & destination> science.doc science.doc $ cp /home/bill/school /home/patrick/
- 33. Copying Files & Directories (cp Commands) $ cp <existing file or dir> <new filename & destination> science.doc science.doc $ sudo cp /home/bill/school /home/patrick/
- 34. Copying Files & Directories (cp Commands) $ cp <existing file or dir> <new filename & destination> science.doc science.doc $ sudo cp -r /home/bill/school /home/patrick science.doc
- 35. Copying Files & Directories (cp Commands) $ cp <existing file or dir> <new destination> $ cp file1 file2 (copy file1 to a new file file2 same location) $ cp file1 ../projects/ (copy file1 to the new location) $ cp -r folder1 ../projects/ (copy the folder with its contents) $ cp -r folder1 ../projects/folder2 (copy the folder with new name) $ cp /etc/passwd . (copy the file …to here )
- 36. Moving/RenamingFiles & Directories (mv Command) $ mv <existing file or dir> <new filename & destination> science.doc
- 37. Moving/RenamingFiles & Directories (mv Command) $ mv <existing file or dir> <new filename & destination> $ mv ~/books/science.doc ~/school/science.doc science.doc $ mv ~/books/science.doc ~/school/
- 38. Moving/RenamingFiles & Directories (mv Command) $ mv <existing file or dir> <new filename & destination> science.doc $ mv /home/bill/school /home/patrick/
- 39. Moving/RenamingFiles & Directories (mv Command) $ mv <existing file or dir> <new filename & destination> science.doc $ sudo mv /home/bill/shool /home/patrick/
- 40. Moving/RenamingFiles & Directories (mv Command) $ mv <existing file or dir> <new filename & destination> science.doc $ sudo mv -r /home/bill/school /home/patrick science.doc
- 41. Moving/RenamingFiles & Directories (mv Command) $ mv <existing file or dir> <new destination> $ mv file1 file2 (rename file1 to file2) $ mv file1 ../projects/ (move file1 to the new location) $ mv -r folder1 ../projects/ (move the folder with its contents) $ mv -r folder1 ../projects/folder2 (move with new name)
- 42. Removing files and Directories (rm Command) $ rm [options] <file or dir list> file.cfgprog1prog2prog3 util1 util2
- 43. Removing files and Directories (rm Command) $ rm [options] <file or dir list> file.cfgprog1prog2prog3 $ cd /usr/local/sbin util1 util2
- 44. Removing files and Directories (rm Command) $ rm [options] <file or dir list> file.cfgprog2prog3$ rm prog1 util1 util2
- 45. Removing files and Directories (rm Command) $ rm [options] <file or dir list> prog2prog3$ rm ../etc/file.cfg util1 util2
- 46. Removing files and Directories (rm Command) $ rm [options] <file or dir list> prog2prog3$ cd ../bin util1 util2
- 47. Removing files and Directories (rm Command) $ rm [options] <file or dir list> util1 util2 $ rm prog3 prog2
- 48. Removing files and Directories (rm Command) $ rm [options] <file or dir list> util1 util2 $ cd /usr/bin/utils
- 49. Removing files and Directories (rm Command) $ rm [options] <file or dir list> $ rm -r /usr/bin/utils util1 util2
- 50. Removing files and Directories (rm Command) $ rm [options] <file or dir list> util1 util2 $ cd -
- 51. Removing files and Directories (rm Command) $ rm [options] <file or dir list> $ rm -r /usr/bin/utils
- 52. Removing files and Directories (rm Command) $ rm [options] <file or dir list> $ rm file1 file2 (remove file1 and file2) $ rm -r ../projects/folder1 (remove the folder with its content) $ rm -i file1 file2 (interactive, ask me before you remove) $ rm -f ../projects/folder1 (force, force remove) • Note • To remove directories you need always to use ‘-r’ • You can not remove your current directory (or any of its parents)