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+Return to [[os:|Operationg Systems home]]
+----
+====== Operating Systems Course: Lab01 ======
+===== Laboratory number 01 =====
+==== Exercise 01: Management of files and directories ====
+=== Part 01 ===
+Produce the following tree of directories in your home directory:
+<file>
+               osEx01
+                  |
+      ------------------------
+      |           |          |
+     src         bin       test
+      |                      |
+   ----------            -----------
+   |        |            |         |
+  include  lib         script   results
+</file>
+=== Part 02 ===
+  * Download the file: [[https://www.skenz.it/listing/os/lab/lab01e01in.txt|lab01e01in.txt]]
+  * Copy the file in the directory ''src'', then, using the directory ''src'' as the current directory, copy the file in the directories ''test'', ''script'', and ''results'' (to this extent use only absolute paths).
+  * Check the existence of the files previously created, and check their rights.
+  * Use the commands ''more'', ''less'' and ''cat'' to verify the content of the files.
+  * Use the command ''diff'' to verify that all the files have the same content.
+  * Without changing the current (working) directory, cancel using relative paths all the files previously created.
+  * Repeat the same sequence of operations starting from father directory of ''src'', i.e., ''osEx01''.
+=== Part 03 ===
+Executing all the commands from the root of your user (i.e., ''/home/username''), do the following:
+  * Copy all the directory tree named ''osEx01'' into a directory tree named ''osEx01backup'', by using the command ''cp'' to copy individual files and the command ''mkdir'' for directories.
+  * Cancel all the content of ''osEx01'' by using the command ''rm'' to remove individual files and the command ''rmdir'' for directories".
+  * Repeat both the //copy// and the //cancel// operations by using the //recursive// versions of the commands ''cp'' and ''rm''.
+=== Part 04 ===
+Check what they do and for what the following commands are used:
+  * ''pwd''
+  * ''wc''
+  * ''history''
+For any problem, remember that you can use the following command to obtain an online help manual for a specific ''command'':
+  * ''man <command>''
+==== Exercise 02: Permissions management ====
+Verify and reply to the following questions:
+  * the ''username'' and the ''group'' to which you belong.\\ Is it possible to modify them?
+  * the position of your home directory within the file system hierarchy of the system you are using
+  * the structure of your ''/home'' directory (e.g., its subdirectories, etc.)
+  * the rights of reading and writing on the various directories of the file system. Is it possible to modify access rights to your ''home'' directory?
+  * what happens if //reading// or //execution// rights are eliminated for a directory. Use both the octal notation (e.g., "654") and the one based on characters (e.g., "+uw-gx") to modify the rights.
+How is it possible to modify in the same way the access rights to **all** the files and directories of a directory tree (for example, to eliminate the //read// right to all, user, group, and other of the directory ''osEx01backup'')?
+==== Esercise 03: Link and comparisons between files ====
+  * Download the file [[https://www.skenz.it/listing/os/lab/lab01e03in.txt|lab01e03in.txt]]
+  * In the same directory where the file is stored, you have to create:
+    * A copy of the file with the name ''lab01e03in.copy''
+    * A hard-link to the file with name ''lab01e03in.hl''
+    * A soft-link to the file with name ''lab01e03in.sl''
+  * View files information with the command ''ls -l''
+    * What can you see in the second column of the output?
+    * Why don't all the files have the same size?
+  * Check that the content of the three created files is the same as the original file using the ''diff'' command.
+    * Why does the ''lab01e03in.sl'' file have a different size than the others, but it has the same content?
+  * Open and modify the content of the file ''lab01e03in.txt'' with a text editor of your choice
+    * How do you expect information related to the size and the date of last modification of the file will be changed? Why?
+    * Verify your answer using the command ''ls -l''
+    * What changes are expected regarding the content of the files? Why?
+    * Check the response by comparing the three files created with the original one. Use again the ''diff'' command.
+  * Rename the file ''lab01e03in.txt'' in ''lab01e03in.backup''
+    * What can you see now from the output of the ''ls -l'' command?
+    * Compare the content of the file ''lab01e03in.backup'' with the content of the files ''lab01e03in.hl'' and ''lab01e03in.sl''. Why in the second case do you obtain an error message?
+  * Create a new empty file named ''lab01e03in.txt''
+    * What is the current expected content of the file ''lab01e03in.sl''? Why?
+    * Check with the command ''cat''
+**Observation:**\\
+The command\\
+''touch <nomefile>''\\
+allows to update date and time of the last modification performed on a file.\\
+In the case the specified file does not exist, it creates an empty file with that name.
+==== Exercise 04: C programs and compilation ====
+Perform the following tasks using:
+  * an editor of your choice (e.g., ''vim'', ''emacs'', ''gedit'', etc.)
+  * the ''gcc'' compiler (alternatively use an IDE of your choice, e.g., CodeBlocks).
+=== Part 01 ===
+Write a C language program that, using the ANSI C I/O primitives (''fgetc''/''fputc'', ''fscanf''/''fprint'',''fget''/''fputs'' of your choice), is able to copy a text file to an identical file.\\
+The name of the two files is received on the command line, so that the program can be executed using a command that specifies three parameters:\\
+''nameExcutable sourceFile destinationFile''
+=== Part 02 ===
+Compile the source files using ''gcc''
+  * Eliminate possible warnings.\\
+  * Try to compile the file by directly generating the executable, or first the object code and then the executable.
+  * Run the program using the [[https://www.skenz.it/listing/os/lab/lab01e01in.txt|lab01e01in.txt]] file as a test file.
+  * Verify the program using as program arguments both //relative paths// and //absolute paths// to specify input and output files.
+  * Verify the correct copy of the files (i.e., ''sourceFile'' and ''destinationFile'' must be identic) using the shell command ''diff''.
+=== Part 03 ===
+How does the written program behave if you try to copy a binary file?
+  * Use the object file or the executable file of the program written to perform a check.
+  * Test its correct functioning using the ''diff'' command.
+=== Part 04 ===
+Change the program using
+  * ANSI C ''fread'' and ''fwrite'' functions (optional) and then
+  * ''open'', ''read'', ''write'', and ''close'' POSIX system calls.
+  * Test its correct functioning using the ''diff'' command.
+==== Exercise 05: Compilation and makefile ====
+  * Compile the program of the previous exercise using a Makefile containing only the compilation target.
+  * Edit the previous Makefile by adding the ''install'' target, which allows to
+    - create a directory, sibling of the work directory and named ''bin''
+    - move the created executable in this directory
+  * Edit the previous Makefile by adding the ''clean'' target, which removes the object file in the current directory
+  * Edit the previous Makefile by adding the ''distclean'' target that calls the ''clean'' target and deletes the ''bin'' directory (which is the sibling of the current directory) and all its content
+  * Edit the previous Makefile using variables to specify the compiler, the compilation options, and the file name.
+Take as reference the example analyzed in classroom: [[https://www.skenz.it/listing/os/u02-Linux-environment/u02s02e/01-compiler/Makefile4|Makefile4]]

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