Conditionals

Making Decisions

Shell scripts can take different actions based on conditions. The if statement is the primary tool for this.

Basic if / else

if [ condition ]; then
  echo "condition is true"
else
  echo "condition is false"
fi

The [ command evaluates the condition and returns true or false. fi ends the block (it is if spelled backward).

File Tests

The most common conditions check whether files exist:

Example:

if [ -f hello.txt ]; then
  echo "File exists"
else
  echo "Not found"
fi

Since hello.txt exists, the output is:

File exists

String Tests

Number Tests

Your Task

Write an if statement that checks whether hello.txt exists. If it does, print File exists. Otherwise, print Not found.