Sponsored Content
Full Discussion: String Arithmetic ?
Top Forums UNIX for Dummies Questions & Answers String Arithmetic ? Post 302336754 by hkansal on Wednesday 22nd of July 2009 06:05:17 PM
Old 07-22-2009
String Arithmetic ?

Hello Experts,

In my shell I need to perform some simple subtraction on a value returned as a result of the "wc" command. The code:

Code:
scanFromLine="100"  ## This is returned as string as a result of some operation

totalLines=`wc -l "${latestLogFile}" | awk '{print $1}'` ## eg: 200

scanFromLine=`$(( ${totalLines} - ${scanFromLine} ))` ## this line throws an error

The error that I get is:
Code:
h1[227]: 200:  not found.

I am very positive that the error is not thrown because of the values being string. Please tell me my mistake here.

Regards,
HKansal
 

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

time arithmetic

Can anyone help please. I am writing a kourne shell script and I am unsure how to do the following: I have extracted a time string from a logfile, and I have another time string I want to compare it to to see if it's later than the time I'm comparing with. i.e. expectedSLA="23:00:00", ... (2 Replies)
Discussion started by: csong2
2 Replies

2. UNIX for Dummies Questions & Answers

arithmetic problem

i am used to making scripts for hp-ux. but lately i tried to make some for solaris. the problem is that when i tried to execute it it gave me an error the "let: not found". why is that? how can i perform an arithmetic function in the solaris shell script? thanks :) (2 Replies)
Discussion started by: inquirer
2 Replies

3. UNIX for Dummies Questions & Answers

arithmetic syntax

okay, I'm a complete beginner, and I keep getting stuck on the syntax here. I want to write a script where I read the current time as minutes and seconds, convert the minutes to seconds, and add the two, then redirect the output to a file. the command takes two arguments, which will also be... (1 Reply)
Discussion started by: paprbagprincess
1 Replies

4. Shell Programming and Scripting

Can I use wc -l with arithmetic expression?

Folks, I am wondering that i can use something like this in one line. For example, $((cat filename > wc -l) / 2) It doesn't work; how to get it work using command substitution? Moreover, is there any option for wc -l not to return filename after the line counts? wc -l filename would... (3 Replies)
Discussion started by: lalelle
3 Replies

5. Shell Programming and Scripting

Help with arithmetic operation

I am using egrep to extract numbers from a file and storing them as variables in a script. But I am not able to do any arithmetic operations on the variables using "expr" because it stores them as char and not integers. Here is my code and the error I get. Any help will be appreciated. #!/bin/sh... (3 Replies)
Discussion started by: emjayshaikh
3 Replies

6. Shell Programming and Scripting

arithmetic in tcsh

Yes I know tcsh sucks for scripting and arithmetic but I have to write a script for multiple users and they all use tcsh. I have this variable that I 'set' with but pulling numbers off of stings with set STUFF = `grep string file | awk command` Now I would like to add up the numbers that... (4 Replies)
Discussion started by: gobi
4 Replies

7. UNIX for Dummies Questions & Answers

Arithmetic: how to??

Hello all, I'd like to know how to perform arithmetic on multiple files. I have got many tab-delimited files. Each file contains about 2000 rows and 2000 columns. What I want to do is to to sum the values in each row & column in every file. The following explains what I want to do; ... (9 Replies)
Discussion started by: Muhammad Rahiz
9 Replies

8. Shell Programming and Scripting

csh arithmetic ?

Hello, Could someone explain how this one is possible: # @ x = 10 - 11 + 3 # echo $x -4 I know that writing script using csh is bad idea, but I need to write few lines. thanks Vilius (2 Replies)
Discussion started by: vilius
2 Replies

9. UNIX for Beginners Questions & Answers

Invalid arithmetic operator on string concatenation

Hello. LEAP_VERSION="4.2" export ARRAY_MAIN_REPO_LEAP=('zypper_local' 'openSUSE-Leap-'"$LEAP_VERSION"'-Non-Oss' 'openSUSE-Leap-'"$LEAP_VERSION"'-Oss' 'openSUSE-Leap-'"$LEAP_VERSION"'-Update' 'openSUSE-Leap-'"$LEAP_VERSION"'-Update-Non-Oss')Seems that the - is interpreted as a numeric... (2 Replies)
Discussion started by: jcdole
2 Replies

10. Shell Programming and Scripting

Arithmetic with bash

I need to divide the number of white spaces by total number of characters in a file using bash. I am able to get the number of white spaces correctly using: tr -cd < afile | wc -c I am also able to get the total number of characters using: wc -c afile How do I divide the first... (2 Replies)
Discussion started by: ngabrani
2 Replies
ARITHMETIC(6)							 BSD Games Manual						     ARITHMETIC(6)

NAME
arithmetic -- quiz on simple arithmetic SYNOPSIS
arithmetic [-o +-x/] [-r range] DESCRIPTION
arithmetic asks you to solve problems in simple arithmetic. Each question must be answered correctly before going on to the next. After every 20 problems, it prints the score so far and the time taken. You can quit at any time by typing the interrupt or end-of-file character. The options are as follows: -o By default, arithmetic asks questions on addition of numbers from 0 to 10, and corresponding subtraction. By supplying one or more of the characters +-x/, you can ask for problems in addition, subtraction, multiplication, and division, respectively. If you give one of these characters more than once, that kind of problem will be asked correspondingly more often. -r If a range is supplied, arithmetic selects the numbers in its problems in the following way. For addition and multiplication, the numbers to be added or multiplied are between 0 and range, inclusive. For subtraction and division, both the required result and the number to divide by or subtract will be between 0 and range. (Of course, arithmetic will not ask you to divide by 0.) The default is 10. When you get a problem wrong, arithmetic will remember the numbers involved, and will tend to select those numbers more often than others, in problems of the same sort. Eventually it will forgive and forget. arithmetic cannot be persuaded to tell you the right answer. You must work it out for yourself. DIAGNOSTICS
``What?'' if you get a question wrong. ``Right!'' if you get it right. ``Please type a number.'' if arithmetic doesn't understand what you typed. SEE ALSO
bc(1), dc(1) BSD
May 31, 1993 BSD
All times are GMT -4. The time now is 07:33 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy