This tag is meant for everything that has to do with mathematical operations. So if you want to ask a question about doing calculations in `awk`, or if you have a question about `bc`, this is the right tag to use.

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2
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3answers
404 views

Calculate and round numbers up in bash

I'm struggling with a slight variation on: How to calculate by taking first field and How to round floating point numbers in shell? I have a file that looks like (space between columns): 1533 ...
2
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2answers
79 views

Assign variable identifier in loop and echo its value

I hope this question is not a duplicate because I've been trying various ways to solve this problem but couldn't find any solution. I have a for loop in which I'd like to store a command output into ...
1
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2answers
22k views

How to add arithmetic variables in a script

I want to accumulate the line size of a number of files contained in a folder. I have written the following script: let a=0 let num=0 for i in folder/* do num=`cat $i | wc -l` ...
1
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4answers
2k views

Error: integer expression expected

I have written a script to determine the Load average on the server as follows: #!/bin/bash loadavg=`top -b -n1 | grep -i load | awk -F, '{print$4}'| awk -F: '{print $2}'` if [ "${loadavg}" -le 1 ...
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3answers
4k views

Shell scripting to divide numbers inside a file

I have a single column and 12 rows. Each row has numerical values. I want to divide each row values by some constant number (say C) using shell (bash) scripting. How to do this ? Thanks in advance..
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1answer
3k views

How to round floating point numbers in shell?

How do I correctly round IEEE 754 floating point numbers on the command line? I want to specify the precision of the output number - the count of fractional digits. Rounding 6.66 to precision 1 ...
1
vote
3answers
852 views

Writing a shell script to take output of an executable and perform some calculation

I am not much familiar with shell script. I want to write a shell script for the following pseudo-code: min=some garbage value for(i=1 to N){ // N and n will be taken as input for the shell script. ...
1
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3answers
281 views

Add or subtract a number from the names of all the files in a directory

I have a number of png and jpg files whose names are numbers, e.g.0100.png, in a directory, How can I add 1 to their names, for example, to get 0002.png and 0003.png from 0001.png and 0002.png ...
1
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2answers
109 views

How does bash's arithmetic work?

read num1 2 read num2 5 echo "$((num1+num2))" 7 echo "$(($num1+$num2))" 7 I referred this. I don't understand how the above both expressions yields same result? Please explain. echo ...
1
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3answers
378 views

Evaluation an expression and rounding up to three decimals

I have an expression "5+50*3/20 + (19*2)/7" I need to round it up to 3 decimal places. The answer to this is 17.92857142857143. When I use the script below it is giving me 17.928. The answer should be ...
1
vote
1answer
4k views

Divide a variable by a number? [duplicate]

Basically I need to convert centimetres to inches which I am trying to do by diving the area in centimetres by 2.54. But I just cannot get this to work. echo "please enter width and then height" ...
1
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2answers
90 views

Aliasing using for or while loop in .bashrc

Can I use a for or while loop when I have similar pattern in the aliases that I put in my .bashrc file? For example, I have: alias c0='ssh computer-1-0' alias c1='ssh computer-1-1' alias c2='ssh ...
1
vote
1answer
287 views

How can subtract 2 floats which have been extracted from 2 other files with BASH [duplicate]

I'm trying to get the difference between two numbers which I have taken from two files. I think my code will make sense: I've tried to make it work by two different methods, didn't work. What I get ...
1
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1answer
45 views

Whats wrong in creating/printing this array?

To find the average time taken to create certain files, I'm using this minutes array, then would simply use bash arithmetic to find the average. However I'm unable to get the difference except for the ...
1
vote
2answers
112 views

modify user-defined System Variables(that is a number) of remote Server machine using ssh?

I want to modify the value of a System Variable of a remote server . The IP of server is 172.16.22.53. The server runs Windows OS,and Cygwin instlled in it.In ...
1
vote
2answers
3k views

case + how to implement equal or less or greater in case syntax

My target is to verify a range of number with (only with case + esac), and print the range. So for example: If the number is between 0 and 80, print >=0<=80 If the number is between 81 and 100 ...
1
vote
1answer
83 views

bash: -eq vs. == and `bc` output type

This snippet of code has been taken from a larger script, (humbly) simulating the non-existing abs() function: [[ $(echo "$val < 0" | bc) -eq 1 ]] && val=$(echo "$val * -1" | bc) So we ...
1
vote
2answers
344 views

How to format decimal number to display the preciding zero but not the trailing ones?

I have the following script on Ubuntu 14.04.1 LTS 64-bit bash command prompt: S=0.030 F=0.150 N=10 reso=20 DIFF=`echo "scale=3; $F - $S" | bc -l` df=`echo "scale=3; $DIFF / $N" | bc -l` is=`echo ...
1
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1answer
210 views

Rounding float numbers in csh

I have a float number stored in a variable $temp, like 3.046789. How we can round this number with 2 digits precision and the result I need is 3.05. The script I have is a csh script.
1
vote
1answer
25 views

Loop over lines of file, partition file and classify each partition

In the following I've put up my code for iterating over lines of a file in order to collect data within a segment from the file in following fashion: Illustration for understanding procedure: segL ...
1
vote
1answer
31 views

Comparing variables in arithmetic

Was wondering if someone can take the time to explain the following: I have a directory of files (PDF), which I place into an array. shopt -s nullglob # Set array ...
0
votes
4answers
293 views

Bash if conditions of variables within intervals

I have some data spread over time intervals, and I want to take some of those data within the time intervals. For example, I have data at times within 1..9, 11..19, etc., and I want to take data ...
0
votes
1answer
33 views

increment a value pulled from a file

I have a cron that I am writing that will repeat every hour, and I need a simple way to pass a counter from the last run to the next run. My plan was to add the number to a file at the end, and then ...
0
votes
2answers
54 views

Script with multiple arithmetic conditions failing

I'm experiencing problems with a script converting numbers to bytes. If the number is large enough to hit gigabytes or terabytes, the script runs as it should. If the number converts to kilobytes, ...
0
votes
1answer
506 views

“too many arguments in [ (test) statement”

this is my first "if-else" script on linux. It gives the error [: too many arguments Code: n=0 if [ $n % 2 -eq 0 ] then echo "even number" fi How to correct it.
0
votes
4answers
121 views

Hexadecimal number sequence checker in Linux?

I have a list of hexadecimal number. I would like to check whether they are in sequence or not. That is, they should be consecutive numbers, in increasing order. In other words, there should be an ...
0
votes
2answers
75 views

Integer input constraints

I want to make an input constraint on read: Terminal Shell; read x read y echo $(($x+$y)) I want to make a constraint of x, I want x to be -100 <= x <= 100. What's the command I insert ...
0
votes
1answer
104 views

TCSH bitwise | operator

How do I use the bitwise logical-or operator, |, in tcsh? I enter @ y = 1001; @ z = 0110; @ x = $y|$z 110: Command not found.
-1
votes
1answer
3k views

Sum of grep results

I need to output the sum of a grep results for a certain time, for now i hard coded the time grep but any help will be very much appreciated, my problem is i cant output the results on the script. If ...
-4
votes
1answer
57 views

Why is setting a variable name giving me “command not found”?

I want to input a number and then add taxes and subtract discounts. I am trying: #!/bin/sh ... final_amount = $(echo "$purchase_amount+($purchase_amount * $tax)-($purchase_amount * $discount)" |bc ...