Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: tee vs output redirection confusion
Top Forums UNIX for Dummies Questions & Answers tee vs output redirection confusion Post 302303200 by radoulov on Thursday 2nd of April 2009 05:44:40 AM
Old 04-02-2009
The command above works like this:

1. Begin executing the cat command reading a chunk of data from its first argument or STDIN (a limited number of bytes that varies from system to system) and passing that data through the pipe to the sort command.
2. Begin executing the sort command: first set up the redirection (f1 gets truncated) then wait for the entire input to come because of the nature of the ordering.

These too commands run in parallel.
Once the cat command has read and passed the first chunk of data, it will try to read the next one and in the case of f1 it won't be available anymore because of the following redirect.

Consider the following:

Code:
% printf 'f1%1000s\n' {1..1000} > f1    
% printf 'f2%1000s\n' {1..1000} > f2
% wc f[12]
   1000    2000 1003000 f1
   1000    2000 1003000 f2
   2000    4000 2006000 total
% cat f[12] | sort -u | wc -l
2000
% cat f[12] | sort -u > f1   
% wc -l f1
1000 f1

 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

log script input and output using tee ?

hi, new to to forum... i've been trying to create a script in tcsh but i'm having a problem with one thing... the script has to keep log of it's input and output so i'm using tee -a log | script | tee -a log this keeps the logs as asked, but it gives me an extra empty prompt (not in the... (0 Replies)
Discussion started by: moseschrist
0 Replies

2. Shell Programming and Scripting

Duplicate output without tee

Hi, Is there anyway to duplicate output without using tee? Let me explain the problem. We are use ssh to login to remote server and save output to a file using tee commands for auditing purposes. When we use vi editor in ssh session, letters get garbled and cant really use vi. Without tee it... (7 Replies)
Discussion started by: eagles1
7 Replies

3. Shell Programming and Scripting

How Unix tee to send pipeline output to 2 pipes ?

Hi, I would like to process, filter the same ASCII asynchronous live data stream in more than one pipe pipeline. So the one pipeline should filter out some records using grep key word and more than one pipes pipelines each should grep for another key words, each set seperately for each... (5 Replies)
Discussion started by: jack2
5 Replies

4. Shell Programming and Scripting

redirection and output

I'm redirecting the output of a command to a logfile, however, if the user is on a terminal I would also like the output to be displayed on the screen. tar tvf some_tarfile >Logfile if the user is on a term then have the output to the Logfile and also be displayed on the screen at the same... (2 Replies)
Discussion started by: nck
2 Replies

5. Shell Programming and Scripting

Redirection output

Hi there I have a script that runs but it outputs everything onto the screen instead of a file. I've tried using the > outputfile.txt however all it does is dump the output to the screen and creates an outputfile.txt but doesn't put anything in that file. Any help would be appreciated ... (6 Replies)
Discussion started by: kma07
6 Replies

6. Shell Programming and Scripting

problem with suppressed output to file using echo and tee command

Hi, When I run the following command in terminal it works. The string TEST is appended to a file silently. echo TEST | tee -a file.txt &>/dev/null However, when I paste this same line to a file, say shell1.sh, and use bourne shell . I run this file in terminal, ./shell1.sh. However I... (1 Reply)
Discussion started by: shahanali
1 Replies

7. Shell Programming and Scripting

Output redirection

We have an application here that does some table queries and then prints the result on screen. I do not have the code of this application (which i will just call "queryCommand"), but what it does is that you call it with some parameters and it prints some info about the query and then the... (5 Replies)
Discussion started by: jolateh
5 Replies

8. UNIX for Dummies Questions & Answers

Output redirection

Hello i am trying to write a script that will redirect the output to a certain file. Here is the code so far: #!/bin/bash ps -e | sort | more > psfile When I execute the script nothing happens since i assume the output was redirected to the file called psfile. When I try to look at the... (1 Reply)
Discussion started by: mfruiz34
1 Replies

9. Shell Programming and Scripting

Redirection of ls -l output

Hi I am making a script where i want to redirect the output of ls -l to a file Example #ls -l fil1.txt > /opt/temp/a.txt ac: No such file or directory I want to capture output of this command like here output is ac: No such file or directory can anyone help (4 Replies)
Discussion started by: anish19
4 Replies

10. Shell Programming and Scripting

output redirection

Hi all I was wondering if there was a slicker way of doing this without the file - awk '{print $2}' FS=":" "${FILE}" > "${TMPFILE}" { read M_GRP_ID || m_fail 1 "Error: Read failed 1 (${FUNCNAME})" read M_GRP_WAIT || m_fail 1 "Error: Read failed 2 (${FUNCNAME})" }... (6 Replies)
Discussion started by: steadyonabix
6 Replies

LEARN ABOUT MINIX

ppmtosixel

ppmtosixel(1)                                                 General Commands Manual                                                ppmtosixel(1)

NAME

       ppmtosixel - convert a portable pixmap into DEC sixel format

SYNOPSIS

       ppmtosixel [-raw] [-margin] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as input.  Produces sixel commands (SIX) as output.  The output is formatted for color printing, e.g. for a DEC
       LJ250 color inkjet printer.

       If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled.  A printer control header and a color assignment table
       begin the SIX file.  Image data is written in a compressed format by default.  A printer control footer ends the image file.

OPTIONS

       -raw   If  specified,  each  pixel  will  be explicitly described in the image file.  If -raw is not specified, output will default to com-
              pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands.  A raw file is often an order  of  magni-
              tude larger than a compressed file and prints much slower.

       -margin
              If  -margin  is not specified, the image will be start at the left margin (of the window, paper, or whatever).  If -margin is speci-
              fied, a 1.5 inch left margin will offset the image.

PRINTING

       Generally, sixel files must reach the printer unfiltered.  Use the lpr -x option or cat filename > /dev/tty0?.

BUGS

       Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion.  If the original PPM maxval was
       greater  than  100,  rescaling  also reduces the image depth.  While the actual RGB values from the ppm file are more or less retained, the
       color palette of the LJ250 may not match the colors on your screen.  This seems to be a printer limitation.

SEE ALSO

       ppm(5)

AUTHOR

       Copyright (C) 1991 by Rick Vinci.

                                                                   26 April 1991                                                     ppmtosixel(1)
All times are GMT -4. The time now is 02:25 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy