Help with While loop using if else


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Help with While loop using if else
# 1  
Old 06-30-2017
Help with While loop using if else

Hi ,
I am executing a while loop .The only condition is , as far as the cumulative sum of the 2nd column from each line passed from the txt file reaches value of 12 , echo those lines .But once the cumulative sum reaches 12 , restart the loop setting the cumulative sum variable to 0 . But in the below snapshot , the cumulative sum is getting set to 0 only at the line 5 instead of 4 . The line 4 is skipped due to this reason during the loop iteration. This is also true at line 7 which also getting skipped as the cumulative sum variable is getting reset to 0 at line 8 in the subsequent iteration. Please help with any suggestions

source file : file_size_num.txt

Code:
1,3,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
2,4,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
3,5,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
4,1,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
5,2,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
6,6,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
7,7,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
8,8,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901

Code:
#!/bin/sh
sum=0
while read line
 do
 var1="$(echo "$line" | awk -F "," '{print $2}')"
 sum=$(expr "$sum" + "$var1")
 echo $sum 
 if [ $sum -le 12 ]
 then
 echo $line
 else
 sum=0
line=$line
 fi
done < file_size_num.txt

output :
in the below snapshot , the cumulative sum is getting set to 0 only at the line 5 instead of 4 . The line 4 is skipped due to this reason during the loop iteration. This is also true at line 7 which also getting skipped as the cumulative sum variable is getting reset to 0 at line 8 in the subsequent iteration.

Code:
-bash-4.2$ sh bash.sh
3
1,3,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
7
2,4,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
12
3,5,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
13
2
5,2,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
8
6,6,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
15
8
8,8,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
-bash-4.2$


Moderator's Comments:
Mod Comment Please use code tags consistently, thanks.

Last edited by zaxxon; 06-30-2017 at 03:46 AM.. Reason: code tags
# 2  
Old 06-30-2017
Try this:
Code:
$ awk -F, 'sum < 12 {print; print sum+=$2; next} {print "RESET"; sum=$2; print; print sum}' infile
1,3,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
3
2,4,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
7
3,5,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
12
RESET
4,1,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
1
5,2,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
3
6,6,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
9
7,7,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
16
RESET
8,8,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
8

# 3  
Old 06-30-2017
Not sure I fully understand what you're after (please apply some care when phrasing your request), and infering from your prompt you have bash, try
Code:
while IFS="," read F1 F2 F3; do ((sum+=F2)); if [ $sum -le 12 ]; then echo $F1,$F2,$F3; else sum=0; fi; done < file
1,3,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
2,4,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
3,5,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
5,2,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
6,6,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
8,8,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901

# 4  
Old 06-30-2017
Moderator's Comments:
Mod Comment This thread is in a support area of the forum - transferring it to "Shell Programming and Scripting".
# 5  
Old 06-30-2017
Quote:
Originally Posted by paul1234
But in the below snapshot , the cumulative sum is getting set to 0 only at the line 5 instead of 4 .
Yes, because what you say you want and what you have written isn't consistent i have take the liberty to annotate your code:


Code:
#!/bin/sh
sum=0
while read line
 do
 var1="$(echo "$line" | awk -F "," '{print $2}')"   
 sum=$(expr "$sum" + "$var1")                       
 echo $sum 
 if [ $sum -le 12 ]                                 # if sum is less or equal 12
 then
 echo $line                                         # then - echo the line
 else
 sum=0                                              # else - reset the sum
line=$line
 fi
done < file_size_num.txt


Notice, that you need to reset the sum not only if it is greater than 12 (this is the effective logic behind the else-part of "-le") but also when 12 exactly is reached. That means:

Code:
#!/bin/sh
sum=0
while read line
 do
 var1="$(echo "$line" | awk -F "," '{print $2}')"
 sum=$(expr "$sum" + "$var1")
 echo $sum 
 if [ $sum -le 12 ] ; then
     echo $line
 fi
 if [ $sum -ge 12 ] ; then
     sum=0
 fi
done < file_size_num.txt

A few words about the rest of your code:

Code:
sum=$(expr "$sum" + "$var1")

This is Bourne-shell-syntax and you shouldn't use it when using bash. bash can handle integers quite well:

Code:
(( sum = sum + var1 ))

The way you extract the value from the line is also not optimal: instead of using an external program (which is costly in terms of resources) do it directly in the shell. Instead of:

Code:
while read line ; do
    var1="$(echo "$line" | awk -F "," '{print $2}')"
done < file_size_num.txt

Do it like this:

Code:
while read line ; do
    echo "$line" | IFS=, read junk var1 junk
    echo "$line"
    echo "$var1"
done < file_size_num.txt


I hope this helps.

bakunin
# 6  
Old 06-30-2017
zaxxon . You are close Smilie

Hi all ,
The below is the expected result . Reset at every point the cumulative sum becomes greater than 12 .

Code:
1,3,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
3
2,4,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
7
3,5,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
12
RESET
4,1,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
1
5,2,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1900
3
6,6,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
9
RESET
7,7,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
7
RESET
8,8,/informatica/apps/logs/fin/ote/TgtFiles/Destination/CWXX/CW1901
8


Last edited by paul1234; 07-01-2017 at 01:27 AM..
# 7  
Old 07-01-2017
Please be aware that zaxxon's proposal resets at "greater than AND equal", and there's a fine line between that and "greater than" (which you requested!), as bakunin already pointed out. We're still not clear WHAT you really mean.
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. Shell Programming and Scripting

My for loop decides to become an infinite loop?

Hi, I was debating if I should put this in the dummies or scripts section, I apologize in advance if I chose poorly. Fairly new to Unix and BASH scripting but I thought I made it fairly well given my limited understanding. However, the output indicates that it's looping and I'm ending up with a... (5 Replies)
Discussion started by: gotreef
5 Replies

6. Shell Programming and Scripting

S# in a for loop - concatenate $(loop counter)

Hi, hope I am posting in the right section. My problem is that I have 2 or more arguments passed and I want to check if the arguments passed exists or not. The first argument should not exist and the remaining others should exist. example: ./shells.sh argument1 argument2 argument3 ... (5 Replies)
Discussion started by: fight4love
5 Replies

7. 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

8. 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

9. 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

10. 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
Login or Register to Ask a Question