grep
grep is a Linux command in the Text Processing category, rated beginner difficulty. Searches for patterns in files using regular expressions. The syntax is grep [options] pattern [file]. Key options and parameters: pattern, file — regex pattern, file(s) to search. It returns matching lines. A practical example: grep "error" log.txt grep -r "TODO" src/ # Recursive search grep -i "warning" log.txt # Case-insensitive grep -l "config" *.ini # List filenames only grep -c "fail" *.log # Count matches per file A close relative is sed, which stream editor for filtering and transforming text. A close relative is awk, which powerful text processing language. Ideal for column-based data and reports. A close relative is sort, which sorts lines of text files alphabetically or numerically. More about this category: Linux text processing commands — grep, sed, awk, sort, cut, tr, and more. Search, filter, transform, and format text content.