Mastering text manipulation with powerful tools
The command line has powerful tools for parsing and manipulating text.
Important note
Regular expressions, also known as regexes, are a sequence of characters that form a search pattern used to match, validate, and extract data from strings. It is a powerful tool used in programming, text processing, and data analysis to search, validate, and manipulate text. Regexes can be quite complex, but they are incredibly powerful. Many of the examples covered next can leverage regexes.
grep
grep pattern filename searches for a pattern within a file. grep -r pattern directory searches recursively within a directory. In this case, pattern can be a regex, as described in the preceding note.
sed
sed 's/old/new/g' filename replaces old with new in a file.
awk
awk '{print $1}' filename prints the first column of a file. awk splits the text in the file into columns based on white space...
