Visit Our UNIX and Linux User Community

Problem with Maths

Thread Tools Search this Thread
Top Forums Shell Programming and Scripting Problem with Maths
# 1  
Old 04-03-2006
Problem with Maths

Heres a script i wrote as a bit of practise. What it does is insert a line in the middle of a file. The line being $1 and the file being $2


rm tempfile
touch tempfile

linenum= `wc -l < $2`
if [ "$linenum" -eq 0 ]
echo $1 >> $2

even=`expr "$linenum" % 2`
if [ "$even" -eq 0 ]
midline=`expr "$linenum" / 2`
midline=`expr "$linenum" / 2`
midline=`expr "$midline" + 0.5`

while [ "$linenum" -gt 0 ]
sed -n '$count p' $2 >> tempfile

if [ "$linenum" -eq "$midline" ]
echo $1 >> tempfile

count=`expr "$count" + 1`
linenum=`expr "$linenum" - 1`
cat tempfile > $2

However when I run this I get the following errors:

testscript: 0: command not found
testscript: [: : integer expression expected
expr: non-numeric argument
testscript: [: : integer expression expected
expr: non-numeric argument
expr: non-numeric argument
testscript: [: : integer expression expected

This would suggest that the expr argument does not have numbers in it. I know I have the variables in double quotes but this should not matter should it. Can anyone help me with any of these errors.
# 2  
Old 04-03-2006
Originally Posted by Quesa
if [ "$linenum" -eq "$midline" ]
Remove the quotes.

For ex:

if [ "$linenum" -eq "$midline" ] must be

if [ $linenum -eq $midline ]

# 3  
Old 04-03-2006
Removing the quotes

I removed the quotes as you said but it doesn't change anything. I still get the same errors as before.
# 4  
Old 04-03-2006
The problem is:
linenum= `wc -l < $2`
No spaces on either side of the equals sign. Get rid of that space between the equals sign anf the first backquote.

Previous Thread | Next Thread
Test Your Knowledge in Computers #85
Difficulty: Easy
Windows 7, Windows 8, Windows RT, Windows Phone 8, Windows Server, and the Xbox One's operating system all used the Windows NT kernel.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Calculate the constant e to 14+ decimal places using integer maths.

Hi guys... I am loving this integer maths thing. 64 bit systems are certainly easier than 32 bit, but hey, I don't intend to leave out my fav' platform. Using one of the 'Brothers' methods, URL inside the code. #!/bin/sh # # #!/usr/local/bin/dash # # Brother's formula . #... (2 Replies)
Discussion started by: wisecracker
2 Replies

2. UNIX for Dummies Questions & Answers

sed Or Grep Problem OR Terminal Problem?

I don't know if you guys get this problem sometimes at Terminal but I had been having this problem since yesterday :( Maybe I overdid the Terminal. Even the codes that used to work doesn't work anymore. Here is what 's happening: * I wanted to remove lines containing digits so I used this... (25 Replies)
Discussion started by: Nexeu
25 Replies

3. Shell Programming and Scripting

Maths in shell scripts

Hi, Need help on this. I need to increment a variable by 1 but retain as 2 characters. I am using expr to do additions: NEWSERIAL=`expr $SERIAL + 1` $SERIAL can range from 01-99. After adding "1", I need the result to be 2 characters, eg: 02+1 = 03. By default expr will truncate the... (4 Replies)
Discussion started by: vchee
4 Replies

4. Shell Programming and Scripting

Simple maths calculator loop.

Hi, I am trying to make a maths calculator that: 1. Prompts the user for a number. 2. Prompts the user for an operation (add, subtract, divide or multiply) 3. Prompts the user for a number. 4. Prompts the user for another operation (same as above) OR the option to get the result for the... (4 Replies)
Discussion started by: johnthebaptist
4 Replies

5. IP Networking

Problem with forwarding emails (SPF problem)

Hi, This is rather a question from a "user" than from a sys admin, but I think this forum is apropriate for the question. I have an adress with automatic email forwarding and for some senders (two hietherto), emails are bouncing. This has really created a lot of problems those two time so I... (0 Replies)
Discussion started by: carwe
0 Replies

6. Shell Programming and Scripting

Using IF statements with maths where the input is not an integer

Hi All I've made a few scripts which using GDAL extract the value of a pixel within a given raster. The purpose is to work out the combine value of every pixel. I thought there may have been an easier way to do this but alas! The code below extracts the pixel value at position X Y. The... (3 Replies)
Discussion started by: StudentFitz
3 Replies

7. Shell Programming and Scripting

Maths with variables

Hello, I'm trying to write a while loop for a decimal value in tcsh which I know can't be done. Instead I want my increments to be one order of magnitude too large and then divide it by 10 when I use the variable. However, I don't know how to divide my variable and set it as another. set... (1 Reply)
Discussion started by: DFr0st
1 Replies

8. AIX

AIX OS problem? network problem?

Dear ALL. I installed AIX OS on customer sites. but Only one site is too slow when I connected telnet, ftp.. Ping is too fast. but telnet and FTP is not connected.. of course i check the configuration file on aix but it's normal. Do any Idea?? thanks in advance. - Jun - (3 Replies)
Discussion started by: Jeon Jun Seok
3 Replies

9. AIX

user login problem & Files listing problem.

1) when user login to the server the session got colosed. How will resolve? 2) While firing the command ls -l we are not able to see the any files in the director. but over all view the file system using the command df -g it is showing 91% used. what will be the problem? Thanks in advance. (1 Reply)
Discussion started by: pernasivam
1 Replies

10. Shell Programming and Scripting

Perl - maths equation - need help

if input to the perl program is ' ( p * ((a+b) * (c+d))) + q ' it shuld give the output as ' pac + pad + pbc + pbd + q ' .can anyone suggest a way to do this ? (7 Replies)
Discussion started by: Anuj8584
7 Replies

Featured Tech Videos