I am trying to add a floating point number to the looping points. My loop is non sequential.
j=9.46
for i in 8.0 7.5 7.0 6.5 ;do
$i = $i + $j |bc
echo '$i'
i also tried
ans=$(( x + y ))
k=$[$i+$j]
i have to add the constant to the looping index and use it in a command later in the script. I am able to echo the output using |bc but can't use it in the script as a variable later.
The bash shell (contrary to ksh93, zsh or yash), can't do floating points in its arithmetic evaluations, but you can always invoke a tool that does. bc is good for arbitrary precision calculation, but here awk may be a better tool as it's good with working with arrays, arithmetic and loops:
awk -v increment=9.46 -- '
BEGIN {
for (i = 1; i < ARGC; i++) print ARGV[i] + increment
}' 8.0 7.5 7.0 6.5
Would output:
17.46
16.96
16.46
15.96
Note that awk outputs floating points numbers with 6 digit precision by default. Add a -o OFMT=%.10g for instance for 10 digit precision (internal calculations will generally be done using C double type numbers with usually 64 bits of precision).
In the loop try something like:
i1=$(echo " $i + $j" |bc)
echo "$i1"
First you should not have spaces around =
Second single quotes will prevent shell from interpret the content of variable
i1=$(bc <<< "$i + $j")
bash, that will use a temp file or a pipe to feed the contents to the command.
|bc". Then it will be easy to store the result in a variable. Hint: post your code at shellcheck.net to find errors