OS Lab 2 - Linux Filesystems - Revizia istoricului

Vserbu la 10 octombrie 2025 15:26

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Vserbu: /* Mount and validate */

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Mount and validate

Vserbu: /* Optional Extensions */

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Optional Extensions

Vserbu la 10 octombrie 2025 13:44

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Vserbu: /* Assessment: Lab Submission Tasks */

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Assessment: Lab Submission Tasks

Vserbu: /* Assessment: Lab Submission Tasks */

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Assessment: Lab Submission Tasks

Vserbu: /* Assessment: Lab Submission Tasks */

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Assessment: Lab Submission Tasks

Vserbu la 10 octombrie 2025 13:19

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Vserbu la 10 octombrie 2025 13:18

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Vserbu la 10 octombrie 2025 13:16

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 * Distinguish common filesystem node types: regular files, directories, symbolic links, block/character devices, FIFOs (named pipes), and Unix domain sockets.
 * Discover mounted filesystems and underlying block devices using <code>df</code> and <code>lsblk</code>, and explain the relationship between them.
-* Manipulate filesystem nodes using standard CLI tools (<code>ls</code>, <code>cp</code>, <code>mv</code>, <code>rm</code>, <code>mkdir</code>, <code>ln</code>, <code>chmod</code>, <code>chown</code>, <code>find</code>, <code>file</code>, <code>stat</code>).
+* Manipulate filesystem nodes using standard CLI tools (<code>ls</code>, <code>cp</code>, <code>mv</code>, <code>rm</code>, <code>mkdir</code>, <code>ln</code>, <code>find</code>, <code>file</code>, <code>stat</code>).
 * Create a loopback block device backed by a file and format it with <code>mkfs.ext4</code>, then mount, verify, and clean it up safely.
@@ Linia 106: / Linia 106: @@
 * '''Space usage''': <code>du -sh DIR</code>, <code>df -hT</code>.
-'''Mini-lab:''' <syntaxhighlight lang="bash">
+'''Mini-lab:'''
 mkdir -p ~/lab-fs/dir1/dir2
 cd ~/lab-fs
@@ Linia 116: / Linia 118: @@
 file notes.txt dir1/pipe link-to-data
 find . -type f -size +0
-chmod 640 notes.txt && stat notes.txt </syntaxhighlight>
+stat notes.txt
 : Note: Sockets are typically created by running daemons. You can spot them with <code>find -type s</code> (e.g., in <code>/run/</code> or <code>/var/run/</code>).

@@ Linia 152: / Linia 152: @@
 <syntaxhighlight lang="bash">
 sudo mkdir -p /mnt/labfs
-sudo mount "$LOOPDEV" /mnt/labfs
+sudo mount /dev/loopX /mnt/labfs
 df -hT /mnt/labfs
-lsblk -f | grep $(basename "$LOOPDEV")
+lsblk -f loopX
 </syntaxhighlight>

@@ Linia 239: / Linia 239: @@
 = Optional Extensions =
-* Create partitions '''inside''' the loop device (<code>sudo sfdisk "$LOOPDEV"</code>), then <code>partprobe</code> and format <code>/dev/loopXp1</code>.
+* Create partitions '''inside''' the loop device (<code>sudo sfdisk /dev/loopX</code>), then <code>partprobe</code> and format <code>/dev/loopXp1</code>.
 * Compare <code>mkfs.ext2</code> vs. <code>mkfs.ext4</code> space usage and features (journaling, extent maps).
-* Mount with options: <code>sudo mount -o noatime,nodiratime "$LOOPDEV" /mnt/labfs</code> and measure <code>stat</code> times.
+* Mount with options: <code>sudo mount -o noatime,nodiratime /dev/loopX /mnt/labfs</code> and measure <code>stat</code> times.
 == Quick Command Cheat Sheet ==

@@ Linia 9: / Linia 9: @@
 * Create a loopback block device backed by a file and format it with <code>mkfs.ext4</code>, then mount, verify, and clean it up safely.
-= Quick Refresher: Paths & Hierarchy =
+= Quick Refresher: Paths and Hierarchy =
 Linux organizes everything in a single tree with <code>/</code> as the root. Example key directories:
@@ Linia 59: / Linia 59: @@
 cat a.sym              # will fail: dangling symlink </syntaxhighlight>
-= Discovering Filesystems & Devices =
+= Discovering Filesystems and Devices =
 Two essential tools:
@@ Linia 99: / Linia 99: @@
 Core commands (read <code>man</code> pages for details):
-* '''List & inspect''': <code>ls -la</code>, <code>tree</code> (optional), <code>file</code>, <code>stat</code>.
+* '''List and inspect''': <code>ls -la</code>, <code>tree</code> (optional), <code>file</code>, <code>stat</code>.
 * '''Create''': <code>touch</code>, <code>mkdir</code>, <code>mkfifo</code>, <code>ln -s</code>, (rarely) <code>mknod</code> for manual device nodes.
 * '''Copy/Move/Delete''': <code>cp</code> (<code>-r</code> for dirs), <code>mv</code>, <code>rm</code> (<code>-r</code> recursive, <code>-i</code> interactive).
 * '''Search''': <code>find</code>, <code>grep</code>.
 * '''View''': <code>cat</code>, <code>less</code>, <code>head</code>, <code>tail</code>, <code>wc</code>.
@@ Linia 121: / Linia 120: @@
 : Note: Sockets are typically created by running daemons. You can spot them with <code>find -type s</code> (e.g., in <code>/run/</code> or <code>/var/run/</code>).
-= Creating & Using a Loopback Filesystem =
+= Creating and Using a Loopback Filesystem =
 Goal: Create a '''file-backed block device''' with <code>losetup</code>, format it as '''ext4''', mount it, and verify via <code>df</code> and <code>lsblk</code>.
@@ Linia 177: / Linia 176: @@
 : '''Safety tip:''' Always unmount before detaching the loop device. Use <code>lsof | grep /mnt/labfs</code> if the mount is busy.
-= Mount Tables & Where Linux Stores Them =
+= Mount Tables and Where Linux Stores Them =
 * <code>mount</code> without args lists mounts.

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 # '''Bonus:''' Provide a solution that does '''not''' use shell expansion (like <code>*.log</code>). Instead, use a more robust tool like <code>find</code> with <code>-exec</code> or <code>xargs</code>.
+=== Submission ===
 Submit a short report with command history snippets and brief explanations (≈1–2 pages).

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 Complete the following tasks and submit a report with your commands and output.
-# '''Real-World Scenario: The Automated Organizer'''
+=== Device to Filesystem Mapping ===
-## ''Imagine your <code>Downloads</code> directory is cluttered. Your task is to write a sequence of commands to automatically clean it up.''
+* Run <code>df -hT</code> and <code>lsblk -f</code>.
-## '''Setup:''' Create a <code>~/cleanup_target</code> directory with at least 10 files, including:
+* Identify the line in each result that corresponds to your <code>/</code> (root) filesystem.
-###* Three <code>.log</code> files (e.g., <code>program1.log</code>).
-###* Three <code>.tmp</code> files (e.g., <code>data.tmp</code>).
+=== Links and Inodes ===
-###* One file larger than 10&nbsp;MB (e.g., <code>truncate -s 15M large_dataset.dat</code>).
+* Create a file <code>original.txt</code>, a hard link <code>hard.link</code>, and a symbolic link <code>symbolic.link</code> to it.
-###* Some other miscellaneous files.
+* Provide the output of <code>ls -li</code> and explain why the inode numbers are the same or different.
-## '''Automation Task:'''
-###* Create subdirectories: <code>logs</code>, <code>temp</code>, and <code>large_files</code>.
+=== Loopback Filesystem Creation ===
-###* Move all <code>.log</code> files into <code>logs</code>.
+* Create a 150&nbsp;MB <code>loop.img</code>, format it with ext4 (label <code>MY_LOOP</code>), and mount it on <code>/mnt/mydata</code>.
-###* Move all <code>.tmp</code> files into <code>temp</code>.
+* Create a file <code>proof.txt</code> inside it containing your name.
-###* Move all files larger than 10&nbsp;MB into <code>large_files</code>.
+* Provide the final output of <code>df -hT /mnt/mydata</code> and <code>lsblk -f</code> showing your mounted device.
-###* Create a <code>cleanup_report.txt</code> listing the contents of the new subdirectories.
-## '''Submission:''' Provide the exact sequence of commands you used.
+=== <code>find</code> Command Practice ===
-## '''Bonus:''' For bonus points, provide a solution that does '''not''' use shell expansion (like <code>*.log</code>). Instead, use a more robust tool like <code>find</code> with <code>-exec</code> or <code>xargs</code>.
+* Provide the <code>find</code> command that lists all files in your home directory (<code>~</code>) larger than 1&nbsp;MB and modified in the last 7 days.

@@ Linia 8: / Linia 8: @@
 * Manipulate filesystem nodes using standard CLI tools (<code>ls</code>, <code>cp</code>, <code>mv</code>, <code>rm</code>, <code>mkdir</code>, <code>ln</code>, <code>chmod</code>, <code>chown</code>, <code>find</code>, <code>file</code>, <code>stat</code>).
 * Create a loopback block device backed by a file and format it with <code>mkfs.ext4</code>, then mount, verify, and clean it up safely.
 = Quick Refresher: Paths & Hierarchy =
@@ Linia 25: / Linia 23: @@
 cd ~
 ls -la </syntaxhighlight>
 = Filesystem Node Types =
@@ Linia 62: / Linia 58: @@
 rm a.txt && cat a.hard # still works; inode persists via hard link
 cat a.sym              # will fail: dangling symlink </syntaxhighlight>
 = Discovering Filesystems & Devices =
@@ Linia 100: / Linia 94: @@
 df -hT ~
 lsblk -f | grep $(df --output=source ~ | tail -1) </syntaxhighlight>
 = Working with Nodes =
@@ Linia 128: / Linia 120: @@
 : Note: Sockets are typically created by running daemons. You can spot them with <code>find -type s</code> (e.g., in <code>/run/</code> or <code>/var/run/</code>).
 = Creating & Using a Loopback Filesystem =
@@ Linia 186: / Linia 176: @@
 : '''Safety tip:''' Always unmount before detaching the loop device. Use <code>lsof | grep /mnt/labfs</code> if the mount is busy.
 = Mount Tables & Where Linux Stores Them =
@@ Linia 202: / Linia 190: @@
 cat /etc/fstab
 </syntaxhighlight>
 = Assessment: Lab Submission Tasks =
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 Submit a short report with command history snippets and brief explanations (≈1–2 pages).
 = Troubleshooting =
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 * '''No free loop device''' — Create one: <code>sudo modprobe loop</code>; or manually: <code>sudo losetup /dev/loop10 loop.img</code>.
 * '''Wrong device formatted''' — Always confirm with <code>lsblk -f</code> before <code>mkfs.*</code>. In a VM, take a snapshot first.
 = Optional Extensions =
@@ Linia 265: / Linia 247: @@
 * Compare <code>mkfs.ext2</code> vs. <code>mkfs.ext4</code> space usage and features (journaling, extent maps).
 * Mount with options: <code>sudo mount -o noatime,nodiratime "$LOOPDEV" /mnt/labfs</code> and measure <code>stat</code> times.
 == Quick Command Cheat Sheet == <syntaxhighlight lang="bash">

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 |-
 | <code>s</code> || Unix socket || Created by programs (e.g., services); list with <code>ls -l</code> or <code>ss -x</code>
-|}                                           |   |                   |   |                                                                                          |
+|}
 '''Explore inode numbers:''' <syntaxhighlight lang="bash">