Linux Lab 4: Redirection and Environment

Authority mappings

Checkpoint 1: Output Redirection

• 1 > vs >> 3 pts
  Redirect echo hello to out.txt with > and then with >>. Show difference.
• 2 2> 3 pts
  Redirect ls /nonexistent errors to err.log using 2>.
• 3 2>&1 3 pts
  Merge stdout+stderr to one file with 2>&1.

Checkpoint 2: Pipes

• 1 pipe intro 3 pts
  Build pipeline: ls -l | wc -l. Explain what it counts.
• 2 top-N pipeline 5 pts
  Build pipeline: sort words.txt | uniq -c | sort -rn | head. Top-N frequency.

Checkpoint 3: Environment

• 1 env variables 3 pts
  echo $HOME, echo $PATH, echo $USER. Explain each.
• 2 PATH append 3 pts
  export PATH=$PATH:/opt/mybin. Verify the change.

Checkpoint 4: Variables

• 1 quoting basics 4 pts
  Set var="Stu Steiner". Show echo "$var" and echo '$var'.

Checkpoint 5: Aliases

• 1 alias + source 4 pts
  alias ll='ls -la'. Add it to ~/.bashrc. Show source ~/.bashrc.