Sponsored Content
Top Forums UNIX for Beginners Questions & Answers How do I determine the best number to use for the bs (block size) operand of the dd command? Post 303011925 by Quenz on Thursday 25th of January 2018 07:01:09 PM
Old 01-25-2018
Quote:
Originally Posted by Corona688
What instructions are you following?
There's a bunch of places online that detail how to make bootable USB drives for Linux distros like Ubuntu on Mac. I can't post a URL, because it says I need to have at least 5 posts. It seems to be the only way to do it from Mac's terminal.

Quote:
Originally Posted by Corona688
It makes little sense to dump a raw ISO to a partition, flash drive is not CDROM. A few odd boot systems do this, but usually you'd install to a flash drive like a hard drive.
I don't quite follow you here. I guess dd stands for dump something? All I knew is the command is able to make bootable media.

Quote:
Originally Posted by Corona688
4M is fine. The point is that it's not left at the default of 512, which would be extremely slow.
I appreciate the suggestion, but I'm looking for a bit more of an explanation. I want to be able to work out an optimal number by myself.

You said 512(M?) would be slow. What about 256? What about 1M? What about 8M? I've seen various suggestions, but not much explanation.

Hopefully that makes sense.

Last edited by Quenz; 01-25-2018 at 08:06 PM.. Reason: Rewording
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

determine the size of a file???

Hello, Can someone please tell me which command to use to determine the size of a file? When I log in to my shell account, I do this $>% ls -als total 632 8 -rw-r--r-- 1 user01 devgrp1 1558 Jul 30 23:25 .kshrc What is "1158"? Bytes? Kilobytes? I apologize if my... (8 Replies)
Discussion started by: alan
8 Replies

2. HP-UX

determine number of xterm connected

i more than one hp-ux 11.0 application server. some of these application server has an xterminal attached to them. ncd900 and ncd400. i would like to know how many xterm is connected to an application server. without physically checking each xterm, can i identify how many xterm? thanks alot. (0 Replies)
Discussion started by: inquirer
0 Replies

3. Shell Programming and Scripting

$A is a number / any other string? How to determine ?

I have a variable (say $A) and while passing it gets either a number or some other string. Now how can test (with if else) whether the variable is just a ne or something else ? Thanks a lot to all in advance C Saha (2 Replies)
Discussion started by: csaha
2 Replies

4. UNIX for Advanced & Expert Users

How to determine the max file size

Does anyone know a way to determine the maximum filesize on a file system on Solaris, HP-UX, AIX, Linux, and OSF1 using the command line? TIA (2 Replies)
Discussion started by: dknight
2 Replies

5. HP-UX

determine the physical size of the hard disk

Hi is there a cmd in hpux 11 to determine the physical size of the hard disk. not bdf command. i have searched the other threads here but cant find an answer. thank you guys (4 Replies)
Discussion started by: hoffies
4 Replies

6. UNIX for Dummies Questions & Answers

Determine switch buffer size

Hi everybody, I need to calculate the tcp buffer size of a network switch, since it's not specified in the manual; how do I do this? I have some machines connected to the switch and I can run some socket tests written in C between these machines (I can choose how many bytes to send and... (0 Replies)
Discussion started by: dimpim
0 Replies

7. Shell Programming and Scripting

determine the number of spaces

Here is a weird question :) i am trying to create a script written in bash that will create configuration files for nagios. As some of you aware is has to be written in the below format: define service{ option1 value1 option2 value2... (6 Replies)
Discussion started by: ppolianidis
6 Replies

8. UNIX for Dummies Questions & Answers

Command for total number of files (and size) across subdirectories?

Hi all... I have a directory called dbrn. This directory contains an unknown number of subdirectories which in turn contain an unknown number of files. What I want to know is: How many files with extention .ABC can be found in /dbrn across all subdirecties, and what is the total size for... (9 Replies)
Discussion started by: Beun
9 Replies

9. Programming

Perl : Inline program to determine file size

Hi, I have 5 files as below $ ll sam* -rw-rw-rw- 1 sam ugroup 0 Mar 21 06:06 sam3 -rw-rw-rw- 1 sam ugroup 0 Apr 3 22:41 sam2 -rw-rw-rw- 1 sam ugroup 17335 Apr 10 06:07 sam1 -rw-rw-rw- 1 sam ugroup 5 Apr 10 07:53 sam5 -rw-rw-rw- 1 sam ugroup 661 Apr 10 08:16 sam4 I want to list out... (4 Replies)
Discussion started by: sam05121988
4 Replies

10. Programming

How to extract operand size in bits of a C program?

Hi I'm new to shell programming. How do I extract the size of an operand in a simple instruction in a C program? Lets say there is an addition a+b somewhere in a C code where a and b are integers. How to extract the size of a & b in bits? Is there something called intermediate code before an... (4 Replies)
Discussion started by: beginner_99
4 Replies
SHELL-QUOTE(1p) 					User Contributed Perl Documentation					   SHELL-QUOTE(1p)

NAME
shell-quote - quote arguments for safe use, unmodified in a shell command SYNOPSIS
shell-quote [switch]... arg... DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands or files with embedded white space or shell globbing characters safely. Here are a few examples. EXAMPLES
ssh preserving args When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and passes them to "$SHELL -c". This doesn't work as intended: ssh host touch 'hi there' # fails It creates 2 files, hi and there. Instead, do this: cmd=`shell-quote touch 'hi there'` ssh host "$cmd" This gives you just 1 file, hi there. process find output It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote: eval set -- `find -type f -print0 | xargs -0 shell-quote --` debug shell scripts shell-quote is better than echo for debugging shell scripts. debug() { [ -z "$debug" ] || shell-quote "debug:" "$@" } With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can. save a command for later shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are things the user can't pass through), you can do something like this: user_switches= while [ $# != 0 ] do case x$1 in x--pass-through) [ $# -gt 1 ] || die "need an argument for $1" user_switches="$user_switches "`shell-quote -- "$2"` shift;; # process other switches esac shift done # later eval "shell-quote some-command $user_switches my args" OPTIONS
--debug Turn debugging on. --help Show the usage message and die. --version Show the version number and exit. AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions. AUTHOR
Roderick Schertler <roderick@argon.org> perl v5.8.4 2005-05-03 SHELL-QUOTE(1p)
All times are GMT -4. The time now is 09:33 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy