Building JSON command with bash script

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# 43  
I'd keep it simply with a case statement like in post #41

   mk_json_object_one_val "$btc_amount_dec" "${addr_arr[@]}"
   mk_json_lst_one_val "${addr_arr[@]}"
   echo "\$used_net is: $used_net"
   case "$used_net" in
       testnet) echo "bitcoin-cli -testnet sendmany \"\" {$pairs} 6 Payments [$items] true 6 CONSERVATIVE" ;;
             *) echo "bitcoin-cli sendmany \"\" {$pairs} 6 Payments [$items] true 6 CONSERVATIVE"
   #echo "TxID: $1"

# 44  
Originally Posted by Chubler_XL
I'd keep it simply with a case statement like in post #41

   mk_json_object_one_val "$btc_amount_dec" "${addr_arr[@]}"
   mk_json_lst_one_val "${addr_arr[@]}"
   echo "\$used_net is: $used_net"
   case "$used_net" in
       testnet) echo "bitcoin-cli -testnet sendmany \"\" {$pairs} 6 Payments [$items] true 6 CONSERVATIVE" ;;
             *) echo "bitcoin-cli sendmany \"\" {$pairs} 6 Payments [$items] true 6 CONSERVATIVE"
   #echo "TxID: $1"

Yes, I understand your suggestion but I would like to know what is wrong with the 'test' I'm using there! It's so simple that I can't understand why it's not working!

In the meantime I did another test with my code. I used '' and it works... :s

   mk_json_object_one_val "$btc_amount_dec" "${addr_arr[@]}"
   mk_json_lst_one_val "${addr_arr[@]}"
   echo "\$used_net is: $used_net"
   if [ "$used_net" == "testnet" ]; then
     echo "bitcoin-cli -testnet sendmany "" {$pairs} 6 Payments [$items] true 6 CONSERVATIVE"
     echo "bitcoin-cli sendmany "" {$pairs} 6 Payments [$items] true 6 CONSERVATIVE"
 #echo "TxID: $1"

./ -m -a addr_lst.dat
2 addresses sucessefuly loaded.

$used_net is: mainnet
bitcoin-cli sendmany  {"n1yswZYByRv3okGDHs1oDaevq8gsDaYZzC":"0.00256372","2NFafKRugHFdYEib7xVfkT6bvtkUKK8oShZ":"0.00256372"} 6 Payments ["n1yswZYByRv3okGDHs1oDaevq8gsDaYZzC","2NFafKRugHFdYEib7xVfkT6bvtkUKK8oShZ"] true 6 CONSERVATIVE

./ -t -a addr_lst.dat
2 addresses sucessefuly loaded.

$used_net is: testnet
bitcoin-cli -testnet sendmany  {"n1yswZYByRv3okGDHs1oDaevq8gsDaYZzC":"0.07931717","2NFafKRugHFdYEib7xVfkT6bvtkUKK8oShZ":"0.07931717"} 6 Payments ["n1yswZYByRv3okGDHs1oDaevq8gsDaYZzC","2NFafKRugHFdYEib7xVfkT6bvtkUKK8oShZ"] true 6 CONSERVATIVE

Last edited by psysc0rpi0n; 10-01-2019 at 07:54 PM..
# 45  
Hello psy,

as you saw in the last post from Chubler and me, that we have different views on what is the preferred choice of coding. I hope this causes not too much confusion for you.

Global And Local Variables

I just checked your code at github and want to mention, that you are using global variables a lot which one should better avoid. Use local variables instead. A global variable is a variable that is accessible and changeable everywhere in the program. There's a danger if a global variable is changed/used where it is unexpected. One may use even the same variable name in different places for different purposes. It most likely will break the program. A local variable is valid only inside of a function in which it is defined.


# this is global
name="tony stark"

give_name() {

     # this is local
     local name="bruce banner"     # <--- this is the local variable name
                                   #      only valid in this function

     echo "$name"                  # <--- echo produces output of local variable name

give_name                          # <--- outputs what function give_name does ("bruce banner")

echo "hello $name"                 # <--- name is the global assigned name "tony stark"

name="$(give_name)"                # <--- assigns output of function 
                                   #      give_name()(="bruce banner") to global variable "name"

echo "hello $name"                 # <--- output newly assigned value of global variable


bruce banner
hello tony stark
hello bruce banner

Function Arguments And Return Values

A recommended way is to put what you need as arguments into your function and return back what you want from the function. Returning back in bash means mostly to print it(echo, printf, ...). (yes, return also exists, but I try to make it easy).

A simple example:

add() { 
   echo "$(( $1 + $2 ))"

sum="$( add "5" "4" )"

The function add takes 2 arguments, adds them and prints them. The output is received from the function and put into the (global) variable sum.

See also: Local Variables

P. S.: To avoid global variables is a good coding practice for starting. If one internalized it, one may break the habit occasionally.

Last edited by stomp; 10-01-2019 at 08:40 PM..
This User Gave Thanks to stomp For This Post:
# 46  
Originally Posted by psysc0rpi0n
Yes, I understand your suggestion but I would like to know what is wrong with the 'test' I'm using there! It's so simple that I can't understand why it's not working!
&& and || control operators examine the exit status last command executed in the list.

If the last command has a zero exit status then a command following && will run:
$ [ 1 -eq 0 ]
$ echo $?
$ [ 1 -eq 1 ] && echo yes

if the exit status is non-zero then the command following || will run:
$ [ 1 -eq 0 ]
$ echo $?
$ [ 1 -eq 0 ] || echo no

This is fairly straight forward so far. However when you string 2 control operators together like this:

$ [ 1 -eq 0 ] || echo no && echo yes

The exist status of the test is non-zero so echo no is executed. Following this the exit status of echo no is examined and found to be zero so echo yes is then executed.

For this reason I avoid stringing && and || control operators together in a single command line.

I don't mind stringing multiple && control operators together, this has the effect of continuing executing of each command as long as it's predecessor succeeds:
command1 && command2 && command3 && command4

--- Post updated at 01:07 PM ---

As a side note I'd like to discuss the code presented by Stomp earlier:

[ "$used_net" == "testnet" ] && btcopt="-testnet" || btcopt=

This works as intended because the command in the middle will always succeed (return a zero exit status) so the end command is not executed.

However, I feel this is a small time bomb waiting for someone to come along later, and because it isn't directly obvious that the execution of the 3rd command is dependent on the exit status of the 2nd (not the original test as many could assume) they change the 2nd command.
$ [ 1 -eq 1 ] && grep NotFound /dev/null || echo no

The above grep is just an illustration, any other command that has the potential to return a non-zero value would break the original intent.
This User Gave Thanks to Chubler_XL For This Post:
# 47  

thanks for the suggestions and explanations.

There is no confusion about different ways of coding. I absolutely understand both approaches.

I'm also aware of global and local variables. I might have gave the wrong idea about me. I have some basic background in programming, mostly C language. So I have minimal and basic understanding about a few programming concepts, but of course I'm no expert. I don't do this for living and never did.

I started using global variables because when I started this script I never thought it would turn this difficult or so big. This was supposed to be a script to run a single command but then I got excited and tried to add some more features and things got more complicated very quickly. So, that's why I started with global variables. one or two variables were supposed to be enough.

I'm perfectly comfortable with generic idea of 'if' and 'case' (switch case in C). I'm not as comfortable with loops as with conditional statements because they can be quite different from C. It's way closer to python but my python knowledge is also very limited.
Passing arguments into functions and calling functions themselves is also a bit different. Anyways, code is almost as I want it to be!...

I'm just bothered with something yet about 'test'.
This function I have in another version of my script, works as I was expecting. I mean, it never runs both commands like the function we have been talking lately about.
Is there any explanation for this:
# ------ Check loaded wallet balance ------ #
   echo "used_net: $used_net"
   echo Checking Full Node data...
   echo Current wallet has:
   [ "$used_net" == "testnet" ] && bitcoin-cli -testnet getbalance\
                                || bitcoin-cli getbalance

This is another example of another function that is working correctly, or at least gives me the expected results, using '[]'.

   [ "$used_net" == "testnet" ] && btc_dec=$(bitcoin-cli -testnet getbalance)\
                                || btc_dec=$(bitcoin-cli getbalance)
   btc_sats=$(echo "$btc_dec * 1*10^8" | bc)
   btc_sats_amount=$(echo "$btc_sats / $num_addr" | bc)
   btc_amount_dec=$(printf "%.8f" $(echo "scale=8; $btc_sats_amount / (1*10^8)" | bc -l))
   echo "$btc_amount_dec"


You examples are next to be tried out in my terminal. Thanks for the simple and clear bits about my questions.


I'll update github files with latest versions of the scripts (versions of) that I'm actually working on.
They are basically the same but one will be to run with no human interference (with cron if possible) and the other one provides menus to run specific tasks by hand.
I'll paste here the link to github when I update the repository!

Eited 2;
I forgot one question.
The function we have been talking lately, the one called "send_multiple_payment" (or "sendmany" or "send_many", I think I've been changing its name from version of script to version of script) will run a command "bitcoin-cli sendmany blablabla........" and this command will return a value which is the transaction ID an it prints it out directly to stdout. I want to be able to show it by myself so I need to omit the output given by bitcoin-cli and fetch it somehow manually and print it myself using my code. I can I do this? I think I can redirect the command output with that thing "2>&1" or whatever it is but then how do I get it to be able to print it myself?

Last edited by psysc0rpi0n; 10-02-2019 at 06:45 PM..
# 48  
Anyone still around?

I'm trying to cut off global variables in my script but looks like there aren't that many variables I can change scope.
# 49  

I've started to try something new for my script.
I'm trying to iterate over a JSON object, search for a specific value in all keys present in that object and finally, add those values.
Knowing that a specific key value can be accessed by

echo "$json_obj" | jq '.[0] .key'

I tried to use a variable to iterate through all keys and print their values

json_obj=(bitcoin-cli listunspent)
for i in "${#json_obj}";
echo "$json_obj" | jq '.[$i] .address'

But I get the following error which I can't fix.

jq: error: i/0 is not defined at <top-level>, line 1:
.[$i] .address
jq: 1 compile error
I think this means that 'jq' cannot "expand" the $i variable so it returns that error, but I have no idea how to fix this!

Any help?

I even tried this, but couldn't make it work either
Bash for Loop Over JSON Array Using jq

Last edited by psysc0rpi0n; 10-14-2019 at 08:09 PM..
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