Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

Loop questions

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Loop questions
# 15  
Old 02-10-2013
You have a few issues with your posted script.
  • $date is not set - put date=`date +%Y%m%d` near the top
  • cp requires at least two path/file args (source and dest) so that is why your cp command is throwing errors, try cp /data1/test /data1/test_${date}_$i
# 16  
Old 02-11-2013
Quote:
Originally Posted by Chubler_XL
You have a few issues with your posted script.
  • $date is not set - put date=`date +%Y%m%d` near the top
  • cp requires at least two path/file args (source and dest) so that is why your cp command is throwing errors, try cp /data1/test /data1/test_${date}_$i
Code:
#!/bin/bash

dd if=/dev/urandom of=/data/test bs=128M count=40

for ((i=1;i<=200;i++));
do

   cp /data/test /data/$i
   echo "loop $i"
   date 
done

rm -rf /data/$i /data/test

thanks this is what i did and it seems running fine so far.
but my question here is it creates only 5GB of file...what you think if i'd like to make it 20Gb or 30GB file.
if i do dd will be memory hog to create such big file ?

also i'd like to create a file called file1, file2...file200 instead of 1 2 3...200.

would be glad to hear.

thanks
Last edited by Scrutinizer; 02-11-2013 at 12:58 PM.. Reason: code tags
# 17  
Old 02-11-2013
If you increase the count instead of bs, memory usage will be fine (note 40x128Mb=5G 160x128Mb=20G)

For you filename request, change to cp /data/test /data/file$i and adjust rm command at end (if you want to delete all created files use rm /data/file* /data/test
# 18  
Old 02-11-2013
Quote:
Originally Posted by Chubler_XL
If you increase the count instead of bs, memory usage will be fine (note 40x128Mb=5G 160x128Mb=20G)

For you filename request, change to cp /data/test /data/file$i and adjust rm command at end (if you want to delete all created files use rm /data/file* /data/test
got it thanks much for your help.
last one...
lets say i've 50TB data storage...above will do 4TB only..sometimes i've above 50TB storage...
is there something i can add a line or two like

if it fills up the drive then rm -rf /data1/file*
if space available lets say after 5TB then continue until fill up..

which loop would be best to use.

thanks alot.
# 19  
Old 02-11-2013
You could keep doing cp command until it fails (something like Corona688 suggested back in post #2)
Code:
#!/bin/bash

dd if=/dev/urandom of=/data/test bs=128M count=40

i=1
while cp /data/test /data/file_$i
do
   echo "`date`: Loop $i"
   let i=i+1
done

printf "Removing files now..."
rm -f /data/file_* /data/test
printf "\n"
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

For loop or while loop from a text file

Hi all, i developed a script to measure the uptime of a process in a Solaris 10/11 environments. All is well, but i came across a situation where there are multiple processes of the same name. Basically i have the following result file: beVWARS 13357 19592122 beVWARS 14329 19591910... (4 Replies)
Discussion started by: nms
4 Replies

2. Shell Programming and Scripting

awk loop using array:wish to store array values from loop for use outside loop

Here's my code: awk -F '' 'NR==FNR { if (/time/ && $5>10) A=$2" "$3":"$4":"($5-01) else if (/time/ && $5<01) A=$2" "$3":"$4-01":"(59-$5) else if (/time/ && $5<=10) A=$2" "$3":"$4":0"($5-01) else if (/close/) { B=0 n1=n2; ... (2 Replies)
Discussion started by: klane
2 Replies

3. Shell Programming and Scripting

Reset while loop to loop same file multiple times

Hi, I want to read file multiple times. Right now i am using while loop but that is not working. ex. While read line do while read line2 do echo stmt1 #processing some data based on data., done < file2.txt done < file1.txt # This will have 10... (4 Replies)
Discussion started by: tmalik79
4 Replies

4. Shell Programming and Scripting

Array Variable being Assigned Values in Loop, But Gone when Loop Completes???

Hello All, Maybe I'm Missing something here but I have NOOO idea what the heck is going on with this....? I have a Variable that contains a PATTERN of what I'm considering "Illegal Characters". So what I'm doing is looping through a string containing some of these "Illegal Characters". Now... (5 Replies)
Discussion started by: mrm5102
5 Replies

5. Homework & Coursework Questions

Print questions from a questions folder in a sequential order

1.) I am to write scripts that will be phasetest folder in the home directory. 2.) The folder should have a set-up,phase and display files I have written a small script which i used to check for the existing users and their password. What I need help with: I have a set of questions in a... (19 Replies)
Discussion started by: moraks007
19 Replies

6. Shell Programming and Scripting

BASH loop inside a loop question

Hi all Sorry for the basic question, but i am writing a shell script to get around a slightly flaky binary that ships with one of our servers. This particular utility randomly generates the correct information and could work first time or may work on the 12th or 100th attempt etc !.... (4 Replies)
Discussion started by: rethink
4 Replies

7. Shell Programming and Scripting

Null Handling in Until loop. . .loop won't stop

Hi Im running this script, which is supposed to find the max value build some tables and then stop running once all the tables are built. Thing is , it keeps assigning a null value to $h and then $g is null so it keep building tables i.e. testupdateNUL. How can I stop this? Here is what I have: ... (4 Replies)
Discussion started by: brandono66
4 Replies

8. Shell Programming and Scripting

Using variables created sequentially in a loop while still inside of the loop [bash]

I'm trying to understand if it's possible to create a set of variables that are numbered based on another variable (using eval) in a loop, and then call on it before the loop ends. As an example I've written a script called question (The fist command is to show what is the contents of the... (2 Replies)
Discussion started by: DeCoTwc
2 Replies

9. Shell Programming and Scripting

Is there a better way I could have run this loop. (For loop with two variables)

Sorry for such a dreadful title, but I'm not sure how to be more descriptive. I'm hoping some of the more gurutastic out there can take a look at a solution I came up with to a problem, and advice if there are better ways to have gone about it. To make a long story short around 20K pieces of... (2 Replies)
Discussion started by: DeCoTwc
2 Replies

10. Shell Programming and Scripting

how to get the similar function in while loop or for loop

Dear all How to write the shell script for the following statement: (C programming) for (i=0;i<30;i++) { if i=1 continue *skip this number (To do function here....) ... } similar statement in while loop.... I wrote the script in sh... (3 Replies)
Discussion started by: trynew
3 Replies
Login or Register to Ask a Question