File Viewing & Editing – Linux Teaching Plan

This 3‑hour workshop introduces the most common Linux utilities for inspecting and modifying files. It is ideal for students who already know how to navigate a filesystem but need to learn how to read, search, and edit text data in a console‑only environment.

Learning Objectives

Open and read files from the terminal using cat, less, more, head, and tail.
Search within files using grep and regular expressions.
Perform simple text transformations with sed and awk.
Edit configuration and script files with lightweight (nano) and advanced (vim) editors.
Compare files and detect differences with diff and comm.
Apply best practices for file safety and version control basics.

Schedule Overview

0‑10 min – Intro & agenda
10‑25 min – Basic file viewing: cat, less, more
25‑40 min – Quick heads/tails: head, tail
40‑55 min – Pattern search: grep
55‑70 min – Streaming edits: sed
70‑85 min – Column processing: awk
85‑100 min – Editing with nano and vim
100‑115 min – Comparing files: diff, comm
115‑120 min – Wrap‑up & assessment

Command Topics & Hands‑On Exercises

1. `cat` – Concatenate & Display

Displays the entire contents of a file on standard output.

cat README.md

Combine multiple files:

cat file1.txt file2.txt > merged.txt

Create a small file hello.txt with the text “Hello World” and display it with cat.
Concatenate hello.txt and world.txt into greeting.txt.

2. `less` – Page‑wise Viewer

Allows forward/backward navigation through large files.

less /var/log/syslog

Search inside the file:

/error

Open greeting.txt with less and search for the word “Hello”.
Use the F key to tail the file live.

3. `more` – Simple Pager

Older, less feature‑rich pager. Good for quick one‑page look.

more greeting.txt

Open a file larger than 50 KB with more and navigate using Space and b.

4. `head` – Show First Lines

Prints the first 10 lines by default.

head /etc/passwd

Custom line count:

head -n 20 /etc/passwd

Show the first 5 lines of /etc/hosts.
Use head -c 100 to display the first 100 bytes.

5. `tail` – Show Last Lines

Prints the last 10 lines by default.

tail /var/log/kern.log

Follow a file in real‑time:

tail -f /var/log/syslog

Show the last 3 lines of greeting.txt.
Follow syslog for 10 seconds, then exit.

6. `grep` – Pattern Search

Finds lines matching a pattern (regular expression).

grep -i "error" /var/log/syslog

Recursive search:

grep -r "TODO" .

Find all lines containing the word “root” in /etc/passwd.
Search recursively for the string “LICENSE” in the current directory.
Print line numbers with -n.

7. `sed` – Stream Editor

Performs in‑place or streamed transformations.

sed 's/foo/bar/g' file.txt

Delete lines:

sed '/^#/d' file.txt

Replace all occurrences of “cat” with “dog” in greeting.txt and show the result.
Delete all comment lines (starting with #) from a script file.
Use -i to edit the file in place.

8. `awk` – Field Processor

Processes text line‑by‑line using fields.

awk -F: '{print $1,$3}' /etc/passwd

Sum a column:

awk '{sum += $1} END{print sum}' numbers.txt

Print the first and last fields of each line in /etc/passwd.
Calculate the total size of files listed in filesizes.txt.
Filter lines where the second field is > 1000.

9. `nano` – Simple Text Editor

Keyboard‑friendly editor for quick edits.

nano /etc/hostname

Save with Ctrl+O, exit with Ctrl+X.

Open greeting.txt with nano, add a new line, and save.
Use Ctrl+W to search for a word.

10. `vim` – Powerful Text Editor

Modal editor with extensive features.

vim /etc/hosts

Insert mode: i, save: :w, quit: :q, save & quit: :wq.

Insert “# Added by user” at the end of hosts and save.
Search for “127.0.0.1” with /127.0.0.1 and jump to next with n.
Replace all occurrences of “example.com” with “myserver.local” using :%s/example.com/myserver.local/g.

11. `diff` – Compare Files

Shows line‑by‑line differences.

diff old.txt new.txt

Unified format:

diff -u old.txt new.txt

Compare two versions of greeting.txt and identify the changes.
Generate a unified diff and redirect it to changes.patch.

12. `comm` – Compare Sorted Files

Requires sorted input; outputs three columns: unique to file1, unique to file2, common.

comm file1.txt file2.txt

comm -12 file1.txt file2.txt   # common lines only

Sort list1.txt and list2.txt then use comm to find common items.
Show items unique to each file.

Practice Session (Hands‑On)

Students will work in pairs to complete the exercises above. The instructor circulates to provide guidance and ensure that the “safety first” mindset is reinforced:

Always preview changes with cat or less before editing.
Use sed -i or awk with caution; keep backups.
Validate configuration files with syntax‑checking tools (e.g., shellcheck for shell scripts).

Assessment

Quiz (5 min): 5 short‑answer questions covering command options and expected output.
Mini‑Project (15 min): Students write a script that:
1. Searches a directory for all .log files.
2. Counts the number of error lines in each log using grep and wc -l.
3. Outputs a summary file.
Peer review of the script and commands used.

Resources & Further Reading

The GNU Readline Manual – command‑line editing.
Linux Man Pages – the definitive reference.
ShellCheck – static analysis for Bash scripts.
Vim Tutorial – interactive learning.

Feel free to adapt the schedule or exercises to suit your students’ skill level or time constraints.

File Viewing & Editing – Linux Teaching Plan

Learning Objectives

Schedule Overview

Command Topics & Hands‑On Exercises

1. cat – Concatenate & Display

2. less – Page‑wise Viewer

3. more – Simple Pager

4. head – Show First Lines

5. tail – Show Last Lines

6. grep – Pattern Search

7. sed – Stream Editor

8. awk – Field Processor

9. nano – Simple Text Editor

10. vim – Powerful Text Editor

11. diff – Compare Files

12. comm – Compare Sorted Files