Unix, create file based on command

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.

did you try `echo my command | grep stackoverflow > ex.txt` or `my command | grep stackoverflow > ex.txt`? The first one will search for `stackoverflow` in the text `my command` and as that doesn't match nothing will be in ex.txt. — Lucas, Mar 16 '16 at 15:36
I tried `my command | grep stackoverflow > ex.txt` and it worked without the `echo` , why is this? — Jonathan, Mar 16 '16 at 15:40
You need to understand the basics of command line parsing done by the shell. Short answer: If you run `echo my command` you are not running `my command` so you will not get its output. You are running `echo` and telling it to *print* the text "my command". — Lucas, Mar 16 '16 at 15:44
@Lucas, thanks for the explanation, got it. Must run it and put that into a text file. Not put the actual text of the command into a file. — Jonathan, Mar 16 '16 at 15:50

score 0 · Accepted Answer · edited Jun 16 '16 at 08:12

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"

I got it working. I used your first suggestion. I just took out 'echo' from my original attempt. — Jonathan, Mar 16 '16 at 15:36

Unix, create file based on command

1 Answers1