File test operators (-f, -d, -e, -r, -w, -x) in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this script?

Consider a file named example.txt that exists and is readable but not executable. What will this script print?

Bash Scripting

if [ -r example.txt ] && [ ! -x example.txt ]; then
  echo "Readable but not executable"
else
  echo "Other"
fi

A Readable but not executable

B Other

C Syntax error

D No output

💡 Hint

Think about what -r and -x check for in a file.

The -r operator checks if the file is readable, and -x checks if it is executable. Since the file is readable but not executable, the condition is true and prints "Readable but not executable".

💻 Command Output

intermediate

What does this script output if mydir is a directory?

Given mydir is a directory, what will this script print?

Bash Scripting

if [ -d mydir ]; then
  echo "Directory exists"
else
  echo "Not a directory"
fi

A Not a directory

B No output

C Syntax error

D Directory exists

💡 Hint

The -d operator checks if the path is a directory.

The -d operator returns true if the file exists and is a directory. Since mydir is a directory, it prints "Directory exists".

💻 Command Output

advanced

What error does this script produce?

What error will this script produce when run?

Bash Scripting

if [ -f ]; then
  echo "File exists"
fi

A File exists

B bash: [: -f: unary operator expected

C No output

D Syntax error: unexpected token

💡 Hint

Check if the -f operator requires an argument.

The -f operator needs a filename to check. Without it, the test command reports 'unary operator expected'.

💻 Command Output

advanced

What is the output of this script if script.sh is executable and writable?

Given script.sh is executable and writable, what will this script print?

Bash Scripting

if [ -x script.sh ] && [ -w script.sh ]; then
  echo "Executable and writable"
else
  echo "Other"
fi

A Executable and writable

B Other

C No output

D Syntax error

💡 Hint

Remember what -x and -w check for.

The -x operator checks if the file is executable, and -w checks if it is writable. Both conditions are true, so it prints "Executable and writable".

💻 Command Output

expert

What is the value of variable result after running this script?

Assuming file.txt exists and is readable but not writable, what is the value of result after this script runs?

Bash Scripting

if [ -e file.txt ]; then
  if [ -r file.txt ] && [ ! -w file.txt ]; then
    result="read-only"
  else
    result="other"
  fi
else
  result="missing"
fi

A missing

B other

C read-only

D Syntax error

💡 Hint

Check the file existence and permissions carefully.

The file exists (-e true), is readable (-r true), and not writable (! -w true), so result is set to "read-only".