Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Multiple jobs reading from same file
Top Forums Shell Programming and Scripting Multiple jobs reading from same file Post 302413218 by Franklin52 on Thursday 15th of April 2010 02:59:03 AM
Old 04-15-2010
Quote:
Originally Posted by erichpowell
Thanks, Franklin52, that's precisely what I had in mind, but what I was actually getting at was the safety of this technique.

I know that multiple processes writing to the same file is a recipe for trouble, understandably, but I was curious whether multiple jobs/processes reading from the same file is also dangerous.

For example, what happens if they both try to read the same block of memory at the same time?

My googling turned up some forum topics about this in C code, where it did seem to be an issue, but I was going to submit jobs to the background like in Franklin52's post. Can I rely on the OS to sort out any conflicts between the processes?
It shouldn't be a problem IMHO to read a file with 3 processes simultaneously.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

Ksh Storing Multiple Files and reading each line in each file.

How would I go about storing multiple file paths in a directory that begin like: 20080402* and run a loop that reads each line of each file thats in a given directory. So far this is what I have: #!/bin/ksh echo "ENTER Reprint Date (YYYYMMDD): " read ReprintDate echo ""... (1 Reply)
Discussion started by: developncode
1 Replies

2. UNIX for Dummies Questions & Answers

Re : Set multiple cron jobs in one crontab file

Hello All, Hopw all is fine. I am newbie to Unix. I am using Bourne Shell (sh). One of the question I have is that I am trying to read XML file and based on reading that XML file I want to run different java programs at different hours. Meaning 05 14 * * * java ./program1 10 14 * * * java... (3 Replies)
Discussion started by: samshaw
3 Replies

3. Shell Programming and Scripting

Create Multiple files by reading a input file and changing the contents

Being new to this area .I have been assigned a task which i am unable to do . Can any one please help me . Hi I have requirement where i have input file XYZ_111_999_YYYYMMDD_1.TXT and with header and series of Numbers and Footer. I want to create a mutiple output files with each file having a... (2 Replies)
Discussion started by: bhargavkr
2 Replies

4. Shell Programming and Scripting

How to ignore single or multiple lines between /* and */ while reading from a file in unix?

I have a file proc.txt: if @debug = 1 then message 'Start Processing ', @procname, dateformat(now(*), 'hh:mm:ss'), @julian type info to client; end if; /* execute immediate with quotes 'insert into sys_suppdata (property, value, key_name) location ''' || @supp_server || '.' ||... (5 Replies)
Discussion started by: kidncute
5 Replies

5. Shell Programming and Scripting

While loop reading file with multiple conditions

Hi Am trying to print the PIDs of process in a file and trying to grep any PID from that file I set the if condition as $value != "PID" and $value != "-" Assign that number to a variable Am confused since am using while loop to read the line from file and again if condition to check those... (2 Replies)
Discussion started by: Priya Amaresh
2 Replies

6. Shell Programming and Scripting

Search & Replace in Multiple Files by reading a input file

I have a environment property file which contains: Input file: value1 = url1 value2 = url2 value3 = url3 and so on. I need to search all *.xml files under directory for value1 and replace it with url1. Same thing I have to do for all values mentioned in input file. I need script in unix bash... (7 Replies)
Discussion started by: Shamkamde
7 Replies

7. Shell Programming and Scripting

Reading multiple directories and file from them

Hello I'm making script for Dallas temperature sensors (DS1820). When a sensor is connected, it shows up as a directory in /sys/bus/w1/devices in format 10-xxxxxxx. Inside the directory is a file called w1_slave which holds the temperature in format t=xxxxx. Each sensor has unique... (2 Replies)
Discussion started by: Klipeti
2 Replies

8. Shell Programming and Scripting

Shell script to run multiple jobs and it's dependent jobs

I have multiple jobs and each job dependent on other job. Each Job generates a log and If job completed successfully log file end's with JOB ENDED SUCCESSFULLY message and if it failed then it will end with JOB ENDED with FAILURE. I need an help how to start. Attaching the JOB dependency... (3 Replies)
Discussion started by: santoshkumarkal
3 Replies

9. Shell Programming and Scripting

Reading multiple lines in a file

Hello, I am new in shell scripting. I need help regarding following. I have 4 files generated by backups daily. I have stored the names of these 4 files into one file. i.e I have 4 files names as a, b, c & d and these names have been put into one file abcd.txt. Now I want to cat each file in... (7 Replies)
Discussion started by: Ali Sarwar
7 Replies

10. Shell Programming and Scripting

Script to read file and run multiple jobs

I have a txt file line1 line2 line3 $!/bin/sh cat /tmp/lus.txt | while read line do esxcli storage vmfs unmap -u $lin -n 4000 done this works but does in one line at a time. how do I do all lines at once simutaeously? Please use CODE tags as required by forum rules! (4 Replies)
Discussion started by: tdubb123
4 Replies

LEARN ABOUT HPUX

ptree

ptree(1)						      General Commands Manual							  ptree(1)

NAME

       ptree - prints the process tree hierarchy

SYNOPSIS

       [pid1|username1 [pid2|username2]...]

DESCRIPTION

       prints  the process tree of all processes that match the specified arguments.  While printing the tree, the child processes are indented to
       the right from their respective parent processes.

   Options
       Prints the tree starting from the children of
		 (usually pid 0).  The default is to print the tree starting from the children of (pid 1).

   Operands
       pid	 Print the process tree for the process ID number specified by pid.

       username  Print the process tree for all the processes from the user specified by username.  Note that only username (and not user ID)  can
		 be specified for this instance.

       If no operands are specified, then prints the process tree of all processes starting from the children of or (if is specified).

EXTERNAL INFLUENCES

   Environment Variables
       If is not specified or is null, it defaults to (see lang(5)).

EXAMPLES

       Print the process tree for pid 100 and for all processes owned by

WARNINGS

       Process information can change while is running; the tree displayed by is only a snapshot in time.  Some data printed for defunct processes
       is irrelevant.

       Users of must not rely on the exact field widths and spacing of its output, as these will vary depending on the system and the  release	of
       HP-UX.

SEE ALSO

       pgrep(1), pkill(1), ps(1), fork(2).

																	  ptree(1)
All times are GMT -4. The time now is 06:26 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy