How to pipe in the result of another UNIX command

Question

Right now I'm using another text file to store the result of one UNIX command and then using that file to run another command, like so:

tr -d "[,|.]" < text > temporary.txt
tr "[A-Z]" "[a-z]" < temporary.txt > result.txt

How do I combine these two into a single line so that I don't have to use a temporary file? The following does not work:

(tr "[A-Z]" "[a-z]" < (tr -d "[,|.]" < text)) > result.txt

I know how to use && but that still requires the use of a temporary holder file.

Possible duplicate: Bash: how to pipe each result of one command to another

Answer 1

Pipes are your friend:-

cat text | tr -d "[,|.]" | tr "[A-Z]" "[a-z]" >result.txt

Answer 2

Try:

1. tr -d "[,|.]" < text | tr "[A-Z]" "[a-z]" > result.txt
2. cat text | tr -d "[,|.]" | tr "[A-Z]" "[a-z]" > result.txt

Both commands do the same job.

What pipe(designated by |) does, is just redirects output of one command to the input of another. So, for example, in foo | bar the output of foo gets redirected into input of bar.