That would not necessarily lead to syntax errors. These are because the parameters are unset/empty. Try double quoting them whatever they are:$(expr "$t1" + "$t2").
If $t1, $t2, $t3, and $t4 expand to integer values, any shell that recognizes:
Code:
if [[ `expr $t1 + $t2` == `expr $t3 + $t4` ]]; then
should also be able to perform arithmetic expansions (which are shell built-ins) instead of invoking the expr utility twice. Try changing the above line to:
Code:
if [[ $(($t1 + $t2)) == $(($t3 + $t4)) ]]; then
If you're using a 1993 or later version of ksh, this will also work if those variables expand to floating point values.
Even if your shell doesn't support arithmetic expansions or if you're dealing with floating point values and you aren't using a recent ksh, you could get rid of one invocation of expr using:
Code:
if [[ `expr $t1 + $t2 - $t3 - $t4` == 0 ]]; then
or, preferably, the non-obsolescent form:
Code:
if [[ $(expr $t1 + $t2 - $t3 - $t4) == 0 ]]; then
If you'd show us some sample contents of your node*.txt files, we can probably also help you replace your four grep and cut pipelines with something faster.
HI there
I am trying to understand Shell scripting to create my own, I am attempting a few examples can anyone tell me what this means?n=$( expr $n + 1)Tried looking on the internet, but just cannot find its anywhere :( .Help please (4 Replies)
Hi All,
I'm writing a shell script in KSH, where I want to store the filename, total record count and actual record count of all the source files. The source files reside in 4 different sub-folders under the same root folder.
Below is code:
#!/usr/bin/ksh... (6 Replies)
Hey there
i want to subtract the content from $b from $a. Each variable has got 18 values (normal numbers from 0 - 99).
How can i subtract them? I know i have to use the expr command, this is what i have till now:
a=`cat Tabelle.dat | awk {'print $4'} | awk -F: {'print $1'}`
b=`cat... (1 Reply)
$ cat > mtable
#!/bin/sh
#
#Script to test for loop
#
#
if
then
echo "Error - Number missing form command line argument"
echo "Syntax : $0 number"
echo "Use to print multiplication table for given number"
exit 1
fi
n=$1
for i in 1 2 3 4 5 6 7 8 9 10
do
echo "$n * $i = `expr $i \*... (1 Reply)
I'm trying to check if a variable'd string is only one character and use that in an if statement the only way I could find is:
$expr "${var}" : . # expr STRING : regrep
where the "." is the grep wildcard for any single character.
Whats wrong with my code here and is there a... (3 Replies)
What is the difference between test expr VS .
For example :
if test 5 -eq 6
echo "Wrong"
and
if
echo "Wrong"
bot will give the same output as Wrong.
Now, what is the difference between these two? though they are producing the same result why we need two?
Any answer will be... (2 Replies)
i am new to shell programming, currently using redhat linux of version
2.4.20-8.
i have problem in executing expr command in the following shell script
$ x=5
$ x='expr $x + 1'
$ echo $x
the output is displaying always
expr $x + 1
Pls guide me for the above query (3 Replies)
Hello!
I want to evaluate some mathematical expressions in a script and I try to use 'expr' command.
Unfortunatally, when I have, for example,
expr 8.2 + 6
the result is 'expr: non-numeric argument'
Why ?
I work on SunOs 5.7.
Thanks in advance
Nathe (5 Replies)
12-09-2014
