Sponsored Content
Full Discussion: Variable File Descriptor
Top Forums Shell Programming and Scripting Variable File Descriptor Post 302585593 by rpaskudniak on Wednesday 28th of December 2011 11:54:20 PM
Old 12-29-2011
Actually, cts, I had tried a syntax for using eval before I posted. I omitted it because my post was long enough. If I recall, it was something like:
Code:
$ fd=4
$ eval 'exec ${fd}> another'

I'm on a windows box right now so I can't be certain but I think the above eval command resulted in a closed shell just as surely as the naked exec command had done. So to repeat my "smiley" (if it may thus be called): Smilie

If you can come up with a variation that does NOT close the shell, it will be progress.

BTW, I just tried that variable form in a Cygwin BASH window. It also failed - could not find 4 - but at least it did not close the shell. Ah, but it also causes all stdout output to be redirected to the target file, making the shell kinda useless. This is both with and without the eval.

More ideas are SOOO welcome!

Rasputin Paskudniak
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

file activity (open/closed) file descriptor info using KORN shell scripting

I am trying to find a way to check the current status of a file. Such as some cron job processes are dependent on the completion of others. if a file is currently being accessed / modified or simply open state I will wait until it is done being processed before attempting the next process on that... (3 Replies)
Discussion started by: Gary Dunn
3 Replies

2. UNIX for Dummies Questions & Answers

File Descriptor Help

What is a file descriptor in Unix?? How to find a file descriptor of a file in Unix?? Does it have anything to do with the Inode numbers?? (3 Replies)
Discussion started by: rahulrathod
3 Replies

3. Programming

File descriptor constant

I have a requirement to close all the file descriptors from 3 to 1024 for a particular application. Right now, this is how I do it .. for ( int i = 3 ; i <= 1024; ++i ) close(i); The change I am looking at is, I want to do away with the number 1024 and replace it with a constant which... (4 Replies)
Discussion started by: vino
4 Replies

4. UNIX for Advanced & Expert Users

File Descriptor Table

Im working on writing a small operating system. I am currently working on implementing dup, dup2, pipe, and close and I need to implement some type of file descriptor table in my PCB. I was wondering if there is anyone who is familiar with linux/unix implementation of these tables who could... (6 Replies)
Discussion started by: Ashaman0
6 Replies

5. Shell Programming and Scripting

Passing a file descriptor

I am trying to right a function which uses a file descriptor to write to a log file. The problem is that the on the print statement the file descriptor is called bad. Now when I first open the file and print to it in the f_open function by passing the descriptor to f_print_log all works well,... (6 Replies)
Discussion started by: robotball
6 Replies

6. Shell Programming and Scripting

File Descriptor

Hello All, Im opening a file desciptor in perl and sending data using print CMD "$xyz". is there a limit to the length of the string that I can give to this CMD at a time. (3 Replies)
Discussion started by: rimser9
3 Replies

7. UNIX for Dummies Questions & Answers

File Descriptor

Hi What the below path contains? /proc/<pid>/fd (1 Reply)
Discussion started by: siba.s.nayak
1 Replies

8. Shell Programming and Scripting

file descriptor KSH

Hello, How can i use file descriptor in a script to read 2 files at the same time and extract line 200 from file 1 and line 500 from file 2. Thanks. (6 Replies)
Discussion started by: LiorAmitai
6 Replies

9. Shell Programming and Scripting

file descriptor count

I am trying to write a script which will only show me the file descriptor count for a process/pid. My script will return me the count only not the whole output. For example, I would like my script to return the output 23 this case, not the whole output. Can anybody please help me how do I get... (11 Replies)
Discussion started by: mohullah
11 Replies

10. Shell Programming and Scripting

redirecting with file descriptor

hello, Someone can help me with redirectors? I am writing this script in bash enviroment on Fedora: exec 4<> /dev/tcp/10.10.11.30/5000 #open socket in input/output strings<&4 >file.txt & I send file descriptor 4 to string command to purge data stream from special char while come from... (3 Replies)
Discussion started by: rattoeur
3 Replies
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 04:07 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy