How to pipe in the result of another UNIX command
Try:
tr -d "[,|.]" < text | tr "[A-Z]" "[a-z]" > result.txtcat 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.