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Building JSON command with bash script

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# 36  
Old 09-26-2019
Originally Posted by psysc0rpi0n
Ok, I'm going to try your examples. This is not trivial for a starter. I've just been reading but not practicing much, so this is not clear at first sight!

--- Post updated at 10:02 PM ---

I don't fully understand what you mean by:


I need to read about expansions!
Fortunately this stuff is pretty well documented. I'd start with Shell Expansions, it's probably best while reading this to have a shell handy and try out the different expansions/substitutions mentioned with something like the pparm script posted above. Ensure you understand why they shell works the way it does.

For example word splitting occurs before pathname expansion, so when a file containing white space is expanded it wont be split.
Parameter and variable expansion occurs before word splitting so variables with white spaces are split:

$ ls
 jason_expand   pparm  'test with space'
$ ./pparm test*
Param 1: test with space
$ VAR="test with space"
$ ./pparm $VAR
Param 1: test
Param 2: with
Param 3: space
$ VAR=test
$ ./pparm ${VAR}*
<work thru the manual and decide what will happen here before trying it>

Last edited by Chubler_XL; 09-26-2019 at 10:04 PM..
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# 37  
Old 09-28-2019
Hello peeps...

I've been changing my script in several ways until I'm good with it.

I'm now trying to run a command depending on the value of a variable but this is not working.
The code that is not working is:

[ "$used_net" == "testnet" ] && btc_dec=$(bitcoin-cli -testnet getbalance)\
                             || btc_dec=$(bitcoin-cli getbalance)

I want to run one of those 2 commands depending on $used_net variable value! The thing is that no matter the value of $used_net, the issued command is always the one after '||'. What am I doing wrong?

# 38  
Old 09-29-2019
Your code is correct and works here as you described it should. So I assume the variable $used_net never is set to the correct "testnet" value.

Check the variable value directly before the shown command.

Another variant to run it:

[ "$used_net" == "testnet" ] && btcopt="-testnet" || btcopt=
btc_dec=$(bitcoin-cli $btcopt getbalance)

Last edited by stomp; 09-29-2019 at 07:17 AM..
# 39  
Old 09-30-2019
Originally Posted by stomp
Your code is correct and works here as you described it should. So I assume the variable $used_net never is set to the correct "testnet" value.

Check the variable value directly before the shown command.

Another variant to run it:

[ "$used_net" == "testnet" ] && btcopt="-testnet" || btcopt=
btc_dec=$(bitcoin-cli $btcopt getbalance)

Ok, I'll try that later today.

You want to explain how bash processes 2 variable atributions within the same line of code? Probably following some rule like left to right or right to left. But what is the return value of a successeful variable attribution (which I think will be the value assigned to 'btc_opt') in case of 'test' go false?
# 40  
Old 09-30-2019
You want to explain how bash processes 2 variable atributions within the same line of code?
It's nearly the same code as yours: If $used_net is "testnet" set btcopts to "-testnet" otherwise set to empty value. A shorthand if-construct.

The return value of a variable assignment is always 0 - unless the command produces a syntax error.
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# 41  
Old 09-30-2019
For readability and later extend-ability i'd advocate an if then else construct:

if [ "$used_net" == "testnet" ] 
    btc_dec=$(bitcoin-cli -testnet getbalance)
    btc_dec=$(bitcoin-cli getbalance)

Or a case statement:
case "$used_net" in
     testnet) btc_dec=$(bitcoin-cli -testnet getbalance) ;;
           *) btc_dec=$(bitcoin-cli getbalance)

# 42  
Old 10-01-2019

Yesterday I couldn't test the code. I was too tired and didn't even came to my laptop.

Today I tested it and the variable "$used_net" is correctly set! I echo'ed it right before testing it with 'test' as I posted in my post #37.

But I might have seen the wrong problem. I mean, the problem is not that it's not issuing the correct command as I said. I'm sorry for messing this. The problem is rather that both commans are buing issued!

   mk_json_object_one_val "$btc_amount_dec" "${addr_arr[@]}"
   mk_json_lst_one_val "${addr_arr[@]}"
   echo "\$used_net is: $used_net"
   [ "$used_net" == "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"

This is the problematic function, which is being called like:

check_args_count "$@"
process_args "$@"

The result is:
$ ./ -m -a addr_lst.dat
2 addresses sucessefuly loaded.

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

When the expected is only:
bitcoin-cli sendmany "" {"n1yswZYByRv3okGDHs1oDaevq8gsDaYZzC":"0.00256372","2NFafKRugHFdYEib7xVfkT6bvtkUKK8oShZ":"0.00256372 "} 6 Payments ["n1yswZYByRv3okGDHs1oDaevq8gsDaYZzC","2NFafKRugHFdYEib7xVfkT6bvtkUKK8oShZ"] true 6 CONSERVATIVE

One extra question:
The 'test' program uses && for true and || for false, right? Does it matters the order we place the code to be executed after the && or the || ? I mean, Does 'test' knows that && is always for true and || is always for false no matter which comes first?

edited 2;
In the meantime I did my test and answered myself:



 [ "$test_str" == "trrue" ] && echo "true1" || echo "false2"
 [ "$test_str" == "trrue" ] || echo "true1" && echo "false2"


Last edited by psysc0rpi0n; 10-01-2019 at 07:21 PM..

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