Unix, create file based on command [duplicate]

Question

I have a command, but I want to get the results into a .txt file I can open. How do I alter my command to allow the results to be put into a text file. I plan to transfer this .txt file to my local desktop.

my command | grep stackoverflow 

I have tried: echo my command | grep stackoverflow > ex.txt Although nothing comes up in the .txt file.

Thanks.

Answer 1

Well, basically use output-redirection

my command|grep stackoverflow > file       #writes output to <file>
my command|grep stackoverflow >> file      #appends <file> with output
my command|grep stackoverflow|tee file     #writes output to <file> and still prints to stdout
my command|grep stackoverflow|tee -a file  #appends <file> with output and still prints to stdout

The pipe takes everything from stdout and gives it as input to the command that follows. So:

echo "this is a text" # prints "this is a text"
ls                    # prints the contents of the current directory

grep will now try to find a matching regular expression in the input it gets.

echo "my command" | grep stackoverflow  #will find no matching line.
echo "my command" | grep command        #will find a matching line.

I guess "my command" stands for a command, not for the message "my command"