Grab exactly one byte from a FIFO, at random intervals Post: 302747897

Sponsored Content

Top Forums Shell Programming and Scripting Grab exactly one byte from a FIFO, at random intervals Post 302747897 by Yoda on Sunday 23rd of December 2012 03:56:40 PM

12-23-2012

Moderator

I don't know what magic it is but I'm getting it right!!

Code:

y: print next byte
n: don't print next byte
q: quit
y
The input byte is:
48  H
y: print next byte
n: don't print next byte
q: quit
y
The input byte is:
65  e
y: print next byte
n: don't print next byte
q: quit
y
The input byte is:
6c  l
y: print next byte
n: don't print next byte
q: quit
y
The input byte is:
6c  l
y: print next byte
n: don't print next byte
q: quit
y
The input byte is:
6f  o
y: print next byte
n: don't print next byte
q: quit
q

I tested it on GNU/Linux and shell /bin/bash

I recommend you to run ps and verify if you have any previous instance of this script & tail command running because I see the listening section is not getting gracefully terminated after selecting option q and I see this is causing the behavior that you mentioned.

Code:

# ps
  PID TTY          TIME CMD
 4787 pts/0    00:00:00 tail
 4788 pts/0    00:00:00 tfifo.sh
26804 pts/0    00:00:00 ps
29197 pts/0    00:00:00 bash

This User Gave Thanks to Yoda For This Post:

Yoda

View Public Profile for Yoda

Visit Yoda's homepage!

Find all posts by Yoda

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Date Intervals

I posted a question on date intervals about a month back asking about how I could be able to go about a user entering the starting year/month/day and an ending year/month/day and then the script automatically cycling through each day of each month of each year that the user has specified. I...

2. Shell Programming and Scripting

Check if 2 files are identical byte-to-byte?

In my server migration requirement, I need to compare if one file on old server is exactly the same as the corresponding file on the new server. For diff and comm, the inputs need to be sorted. But I do not want to disturb the content of the file and need to find byte-to-byte match. Please...

3. Shell Programming and Scripting

Remove a byte(Last byte from the last line)

Hi All Can anyone please suggest me how to remove the last byte from a falt file .This is from the last line's last BYTE. Please suggest me something. Thank's and regards Vinay

4. Shell Programming and Scripting

Divide numbers into intervals

divide input values into specified number (-100 or -200) according to the key (a1 or a2 ....) For ex: if we give -100 in the command line it would create 100 number intervals (1-100, 100-200, 200-300) untill it covers the value 300 in a1. Note: It should work the same even with huge numbers...

5. Ubuntu

expect script for random password and random commands

Hi I am new to expect. Please if any one can help on my issue its really appreciable. here is my issue: I want expect script for random passwords and random commands generation. please can anyone help me? Many Thanks in advance

6. Shell Programming and Scripting

Need to generate a file with random data. /dev/[u]random doesn't exist.

Need to use dd to generate a large file from a sample file of random data. This is because I don't have /dev/urandom. I create a named pipe then: dd if=mynamed.fifo do=myfile.fifo bs=1024 count=1024 but when I cat a file to the fifo that's 1024 random bytes: cat randomfile.txt >...

7. UNIX for Dummies Questions & Answers

A crude random byte generator...

There was an upload recently on generating a pseudo-random file when /dev/random does NOT exist. This does not need /dev/random, /dev/urandom or $RANDOM either... (I assume $RANDOM relies on the /dev/random device in some way.) This code uses hexdump just because I like hexdump for ease of...

8. UNIX for Dummies Questions & Answers

Building intervals

Hi all, I hope you can help me with the following question: I have multiple tables like this: Chr Start End Zygosity Gene chr1 153233510 153233510 het LOR chr1 153233615 153233615 hom LOR chr1 153233701 153233701 hom LOR chr1 ...

9. UNIX for Dummies Questions & Answers

Changing a special line and Byte in a random file

Hello I created 3 files by: dd if=/dev/urandom bs=1024 count=1000000 of=./testfile1 dd if=/dev/urandom bs=1024 count=5000000 of=./testfile2 dd if=/dev/urandom bs=1024 count=10000000 of=./testfile3 Now I want to know how to make a change in a specific byte and/or line of theses files?

10. UNIX for Dummies Questions & Answers

Gap length between intervals

hi all, I wish to calculate the length between intervals whose are defined by a starting and an end possition. The data looks like this: 1 10 23 30 45 60 70 100... The desired output should be: 13 # (23-10) 15 # (45-30) 10 # (70-60)... I don�t know how to operate with different...

LEARN ABOUT SUNOS

shells

shells(4)							   File Formats 							 shells(4)

NAME

       shells - shell database

SYNOPSIS

       /etc/shells

DESCRIPTION

       The shells file contains a list of the shells on the system. Applications use this file to determine whether a shell is valid. See getuser-
       shell(3C). For each shell a single line should be present, consisting of the shell's path, relative to root.

       A hash mark (#) indicates the beginning of a comment; subsequent characters up to the end of the line are not interpreted by  the  routines
       which search the file. Blank lines are also ignored.

       The  following  default	shells are used by utilities: /bin/bash, /bin/csh, /bin/jsh, /bin/ksh, /bin/pfcsh, /bin/pfksh, /bin/pfsh, /bin/sh,
       /bin/tcsh,  /bin/zsh,  /sbin/jsh,  /sbin/sh,  /usr/bin/bash,  /usr/bin/csh,  /usr/bin/jsh,  /usr/bin/ksh,  /usr/bin/pfcsh,  /usr/bin/pfksh,
       /usr/bin/pfsh, and /usr/bin/sh, /usr/bin/tcsh, /usr/bin/zsh. Note that /etc/shells overrides the default list.

       Invalid shells in /etc/shells may cause unexpected behavior (such as being unable to log in by way of ftp(1)).

FILES

       /etc/shells	       lists shells on system

SEE ALSO

       vipw(1B), ftpd(1M), sendmail(1M), getusershell(3C), aliases(4)

SunOS 5.10							    4 Jun 2001								 shells(4)