Cat, Find, Diff options

Question 1

What does cat -n do?

Answer 1

• Numbers all output lines starting from 1
• Displays line numbers before each line of content
• Useful for referencing specific lines in files or debugging

Question 2

How does cat -b differ from cat -n?

Answer 2

• Numbers only non-blank lines (-b) while -n numbers all lines
• Skips empty lines when counting and displaying line numbers
• Better for focusing on actual content lines

Question 3

What is cat -A used for?

Answer 3

• Shows all non-printing characters including tabs, line endings, and control characters
• Displays tabs as ^I and line endings as $
• Essential for debugging whitespace and formatting issues

Question 4

When would you use cat -s?

Answer 4

• Squeezes multiple consecutive blank lines into single blank line
• Reduces excessive whitespace in output
• Useful for cleaning up formatted text with too much spacing

Question 5

What does cat -T accomplish?

Answer 5

• Displays tab characters as ^I (visible tabs)
• Helps identify tab vs space issues in code and configuration files
• Subset of -A option focused specifically on tabs

Question 6

What does diff -u show?

Answer 6

• Unified diff format showing context around changes
• Displays changed lines with surrounding context for better understanding
• Standard format used by version control systems like Git

Question 7

How does diff -i affect comparison?

Answer 7

• Performs case-insensitive comparison of files
• Ignores differences between uppercase and lowercase letters
• Useful when case variations shouldn’t be considered differences

Question 8

What is diff -w used for?

Answer 8

• Ignores whitespace differences (spaces, tabs) when comparing
• Focuses on content changes rather than formatting differences
• Helpful for comparing code files with different indentation

Question 9

When would you use diff -r?

Answer 9

• Recursively compares directories and their subdirectories
• Shows differences in file contents and directory structure
• Essential for comparing entire directory trees or project folders

Question 10

What does diff -q accomplish?

Answer 10

• Quiet mode - only reports whether files differ, not the actual differences
• Returns brief message if files differ or no output if identical
• Useful in scripts when you only need to know if files match

Question 11

How does diff –side-by-side work?

Answer 11

• Displays files in two columns side by side for easy comparison
• Shows matching lines aligned and different lines highlighted
• More visual format for manual file comparison

Question 12

What does find -name do?

Answer 12

• Searches for files and directories by exact name match
• Case-sensitive pattern matching for filenames
• Example: find /home -name “*.txt” finds all .txt files

Question 13

How does find -iname differ from find -name?

Answer 13

• Case-insensitive name search
• Matches filenames regardless of upper/lowercase letters
• Example: find -iname “*.PDF” matches .pdf, .PDF, .Pdf files

Question 14

What is find -type used for?

Answer 14

• Searches for specific file types (f=file, d=directory, l=link)
• Example: find /var -type f finds only regular files
• Essential for filtering results by object type

Question 15

When would you use find -size?

Answer 15

• Searches for files based on size criteria
• Uses +/- for greater/less than: find -size +100M finds files larger than 100MB
• Useful for finding large files consuming disk space

Question 16

What does find -mtime accomplish?

Answer 16

• Searches by modification time in days
• +n means older than n days, -n means newer than n days
• Example: find -mtime -7 finds files modified in last 7 days

Question 17

How does find -exec work?

Answer 17

• Executes command on each found file
• {} represents the found filename, \; terminates the command
• Example: find -name “*.tmp” -exec rm {} \; deletes all .tmp files