You guys are conflating two different POSIX shell mechanisms here. One is the arithmetic expansion and the other is command expansion. These are different.
$(()) denotes arithmetic expansion, and $() denotes command expansion.
Shells that support $() or $(()) generally support both. For older shells that do not support these syntaxes, you need to use backticks (`) for command expansion and arithmetic expansion isn't supported. In arithmetic expansion, Corona rightly reports that you do not need $ to expand variables; however, you do need this in command expansion. For example:
However:
OTOH, if we give it an expr command:
We need explicit variable expansion:
BTW, if we want compatibility with older shells that do not support arithmetic expansion, we generally are not going to be able to use new-style command expansion, so we want something like this, instead:
we dont conflating anything.we are talking just arithmetic expansion about all shell variants.
I was referring to mentioned syntax of "$((x+y))" expression gives error on the some older shells..
In addition, I mentioned what i identified a issue that is maybe a bug in ash.
because of it(false statement) does not give any error at try of 3rd.
Hi all,
I got some problems on executing the following scripts.
Scripts:
if ]; then
echo "M${str}O 0 1" >> ${tempFile}
elif ]; then
echo "M${str}O 1 0" >> ${tempFile}
else
echo "M${str}O 0 0" >> ${tempFile}
fi
Error:
"`;' is not expected."
what's the problem? (2 Replies)
I am receiving an elif error on line 13 and I can not figure out the reasoning behind it. I have added the then statement that I was initially missing. Any help would be great.
#The purpose of this script is for the end user to be able to enter a positive number
#User enters a number
NUM=$1... (4 Replies)
Script Gurus,
Need your help in getting this script to come out of logical error : I have pasted the script below: This script finds disk utilzation ... the script is written for both AIX and SUN OS... and option will be given in the initial to select DB or Non DB... its required for my prj...... (1 Reply)
I am getting below error from this code (which is at line 24):
if ] #this is line24 in code
then
mv $File_source_path/$File_name $File_name'_'`date '+%d%m%y'`
Error:
line 24:
Any help with the syntax. I am putting 2 condition with 'AND' clause.
This is bash shell. (2 Replies)
I am in need of some help. I am not an advance scripter or programmer, I have novice knowledge. I cannot get a script to work as expected. The script basically does an FTP (which I have work perfectly) and writes to a log. However, I want the script to echo "Not Connected" if the FTP fails to... (2 Replies)
Hi All,
I write an script will have some functions... I am getting elif not expected error..
Even tried by using set -x for debug but no use..
Could you please help me out in this
Variables
....
....
....
TEST_SRC()
{
cat ${filesrc} >> ${filetgt}
if ]; then
echo... (12 Replies)
Hi there, new to this forum and I recently encounter this problem:
I tried to use if-elif loop in a while-read loop, something like this:
#!/bin/bash
while read myline1 myline2
do
if ; then
echo "Successful!"
elif ; then
echo "Failed"
fi
done < $1
Input file looks like this:
200... (13 Replies)
Hi all,i have configured the following script to check if the file exists or not,
#!/bin/sh
sleep 30
{
FILEFULL=$1`date +$2`*
if ;
then
echo $FILEFULL exist
else
echo "$FILEFULL File not Found" | mail -s 'server' myaccount@mydomain.com
fi
}
but i have a problem, i need to... (2 Replies)
Hello all,
I have a scenario where I take user input values and accordingly take actions
say I run a script with
sh scriptname -x GB -e txt (txt can also be text)
I have used if clause for the first input (-x GB)and it is working fine
Now for second the scenario is
if
then
echo... (3 Replies)
Hello experts,
I am having problems with ELIF.
Please see the below code :
read a;
read b;
read c;
if || || ; then
echo "EQUILATERAL"
elif || || ; then
echo "SCALENE"
else
echo "ISOSCELES"
fi
This code works fine for the EQUILATERAL case but fails completely for the... (5 Replies)