Searching and finding

Warning

This page is under construction!

Questions to think about:

How can we find files? How can we find things in files?

Commands of the Day

• grep is a contraction of global/regular expression/print. It finds and prints lines in files that match a pattern.

  • regular expressions are patterns that can include wildcards

  • Usage: grep pattern filename

  • grep -w limits to word boundaries

  • grep -n prints the line numbers that match

  • grep -i makes search case-insensitive

  • grep -v inverts the search to output that does not contain the pattern

  • grep -E notes that the pattern is an extended regular expression that can contain wildcards

• find command finds files!

  • -type d or f for directories or files

  • -name matches a name, but look out for order of execution! Filenames with wildcards need quotes. For example, find . -name "*.txt"

• $() to combine commands. Code inside this runs first!

  • For example, wc -l $(find . -name "*.txt")

Resources

This lesson is adapted from The Unix Shell on Software Carpentry.