LinuxQuestions.org - Directing Script output to Memory but without using a pipe |

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - Directing Script output to Memory but without using a pipe | (https://www.linuxquestions.org/questions/programming-9/directing-script-output-to-memory-but-without-using-a-pipe-%7C-652121/)

Directing Script output to Memory but without using a pipe |

I'm trying to run a series of commands to read a live data dump an strip it in various ways on the fly and send those various stripped pieces of data to corresponding files.

For instance I have the following:

Code:

./dumpscript.sh | sed '/print/,/raw/d' | cut -c 1-47 > output.txt

In this case my dumpscript.sh output is piped through "sed" and "cut" to give me the specific stream of data that I need for archiving.

Now at the same time I would like to run a second "cut" with different parameters and output the results to another file. Again this needs to be live on the fly.

I've tried:

Code:

./dumpscript.sh | sed '/print/,/raw/d' | cut -c 1-47 > output.txt ; cut -c 1-18 > output2.txt

However, there's nothing in the second output file.

Any help would be appreciated.

Is there some way that I could use "tee" perhaps? I read in the man page that:

Code:

The `tee' command copies standard input to standard output and also to any files given as arguments.  This is useful when you want not only to

send some data down a pipe, but also to save a copy.

Any suggestions?

The problem with your last command line is that the semicolon is a command separator. Its just like entering the first command, hitting Enter, and then the second.

What you need is a way to send output to a file... and use tee to send the same stream of bytes to another pipeline. The problem is that you cannot both redirect (>) and pipe (|) STDOUT in the same command.

However, this is where sub-shells are useful. There is nothing to prevent you from sending your output to another shell, which can then redirect away. Try this example:

Code:

$ echo Help Me | sed 's/Me/You/' | tee file1 | (cut -c1-4 > file2)

$ cat file1

Help You

$ cat file2

Help

Note that the STDOUT for the current shell is sent along a pipeline, but the STDOUT of the sub-shell is redirected.

How about awk?

Code:

./dumpscript.sh | sed '/print/,/raw/d' | awk '{printf substr($0,1,47) > "output1.txt"; printf substr($0,1,18) > "output2.txt"}'

Cheers,
Tink

Quote:

Originally Posted by Mr. C. (Post 3197511)

Code:

$ echo Help Me | sed 's/Me/You/' | tee file1 | (cut -c1-4 > file2)

$ cat file1

Help You

$ cat file2

Help

Note that the STDOUT the current shell is sent along a pipeline, but the STDOUT of the sub-shell is redirected.

Mr. C.

Thank you so much, I really appreciate your help... That works exactly as I would like, I can't wait to try it on a live system on Monday, It will be far more efficient than my current methods which require quite a bit of manual work.

Thanks, again.