Multiline Mode

By default, ^ and $ match the start and end of the entire string. The multiline flag (m) changes this behavior.

Default Behavior

Only the first "Hello" matches because ^ means start of the entire string.

With Multiline Flag

Now both lines starting with "Hello" match! The m flag makes ^ match at line starts.

Exercises

Full Line Matching

Practical Examples

Log File Example

The s Flag (Dotall)

The s flag makes . match newlines too:

Without s, . doesn't match the newline characters, so the pattern fails.

Practice Playground

Try with m flag:

• ^# - comment lines start
• ^[a-z]+= - config lines
• ^$ - empty lines
• ^\s*$ - blank lines

Key Takeaways

• Default: ^ and $ match string start/end
• Multiline (m): ^ and $ match line start/end
• Use ^...$ with m flag to match entire lines
• The s flag makes . match newlines
• Combine flags as needed: gm, gi, gms