Introduction to Regular Expressions (Regex)
Understand the syntax and core concepts of Regular Expressions for powerful text pattern matching.
What are Regular Expressions?
Regular Expressions, often shortened to Regex, are powerful patterns used for searching and manipulating text.
Think of them as super-powered search terms that can match specific sequences, characters, or even positions within text.
They are widely used in programming, scripting, and command-line tools like grep, sed, and awk in Linux.
Literal Character Matching
The simplest regex matches exact, literal characters. If you search for 'apple', it will find exactly 'apple'.
Let's use the grep command (Global Regular Expression Print) to demonstrate this basic matching.
echo "apple" > fruits.txt
echo "banana" >> fruits.txt
echo "pineapple" >> fruits.txt
grep "apple" fruits.txt
rm fruits.txtAll lessons in this course
- Introduction to Regular Expressions (Regex)
- Advanced Grep with Regex
- Combining Regex with sed/awk
- Capture Groups, Backreferences & Substitution