Filters and Regular Expressions
What is a filter?
Using Filters
Delimited Input
cat
: the simplest filter
Exercise: cat/more
wc
: word counter
Exercise: wc
tr
: transliterate characters
head
/
tail
: select lines
Exercise: head/tail
grep
: select lines matching a pattern
Regular Expressions
Regular Expression Examples
Atomic Patterns
Bracket Expressions
Anchors
Repetition
Alternation
The grep family
Exercise: grep
cut
: vertical slice
paste
: combine files
sort
: sort lines
uniq
: remove or count duplicates
join
: database operator
Exercise: combining filters
sed
: stream editor
awk
: a programmable filter
Exercise:
awk
find
: search for files
Filter summary by type
Produced: 27 Jul 2007