Convert to uppercase

echo "Hi There" | tr 'A-Z' 'a-z'

gives hi there

put individual words on individual lines

echo "Hello sailor" | tr -c 'A-Za-z' '\012'

gives...
Hello
sailor

put individual words on individual lines but don't repeat the carriage return

Note: without the s, you would have a carriage return for each space. Instead, it squashes repeats...but note, contrary to what I read on the man page, it does not squash Heello

echo "Heello  sailor" | tr -sc 'A-Za-z' '\012'
Heello
sailor

...so, it must just squash the last pattern, proven by this...

echo "Heello  sailor" | tr -s 'A-Za-z'
Helo sailor

Replace all chars but the ones specified

echo "Hello sailor" | tr -c 'A-Za-df-z' '\012'

replaces all chars with a carriage return EXCEPT 'e'

gives...
H
llo
sailor

Sorting tricks

• sort +1 - sorts by field 1 - saves a pipe to awk!

Find word frequency

cat | tr -sc 'A-Za-z' '\012' | tr 'A-Z' 'a-z' | sort | uniq -c | sort -n

-- MattWalsh - 11 Mar 2006