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!
Edited;
In the meantime I did another test with my code. I used 'if...then...fi' and it works... :s
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.
Example:
Code:
# 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
Output:
Code:
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).
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:
if the exit status is non-zero then the command following || will run:
Code:
$ [ 1 -eq 0 ]
$ echo $?
1
$ [ 1 -eq 0 ] || echo no
no
This is fairly straight forward so far. However when you string 2 control operators together like this:
Code:
$ [ 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:
Code:
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:
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.
Example:
Code:
$ [ 1 -eq 1 ] && grep NotFound /dev/null || echo no
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:
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:
You examples are next to be tried out in my terminal. Thanks for the simple and clear bits about my questions.
Thanks
Psy
Edited;
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 05:45 PM..
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
Code:
echo "$json_obj" | jq '.[0] .key'
I tried to use a variable to iterate through all keys and print their values
Code:
json_obj=(bitcoin-cli listunspent)
for i in "${#json_obj}";
do
echo "$json_obj" | jq '.[$i] .address'
But I get the following error which I can't fix.
Quote:
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!
Hi All,
I am new to shell scripting, Need your help in creating a shell script which converts any unix command output to JSON format output.
example:
sample df -h command ouput :
Filesystem size used avail capacity Mounted
/dev/dsk/c1t0d0s0 8.1G 4.0G 4.0G 50% /... (13 Replies)
One of the great thing about unix is the ability to pipe multiple programs together to manipulate data. Plain, unstructured text is the most common type of data that is passed between programs, but these days JSON is becoming more popular.
I thought it would be fun to pipe together some command... (1 Reply)
Hello guys,
I want to parse a JSON file in order to get the data in a table form.
My JSON file is like this:
{
"document":{
"page":
},
{
"column":
}
]
},
{
... (6 Replies)
i have a json data that looks like this:
{
"ip": "16.66.35.10",
"hostname": "No Hostname",
"city": "Stepney",
"region": "England",
"country": "GB",
"loc": "51.57,-0.0333",
"org": "AS6871 British Telecommunications PLC",
"postal": "E1"
}
im looking for a way to assign... (9 Replies)
I am trying to automate editing of a json file using bash script.
The file I initially receive is
{
"appMap": {
"URL1": {
"name": "a"
},
"URL2": {
"name": "b"
},
"URL3": {
"name": "c"
},
}
WHat I would like to do is replace... (5 Replies)
All,
Have a weird issue where i need to generate a report from GitHub monthly detailing user accounts and the last time they logged in. I'm using a windows box to do this (work issued) and would like to know if anyone has any experience scripting for GitAPI using windows / cygwin / powershell?... (9 Replies)
Hello,
I would like to modify an existing script of mine that uses a manually defined "MCVERSION" variable and make it define that variable instead based on this JSON file stored online:
https://s3.amazonaws.com/Minecraft.Download/versions/versions.json
Within that JSON, I 'm looking for... (4 Replies)
I need help in writing a BASH SCRIPT of ls command.
for example:
$ ./do_ls.sh files
f1.txt
f2.jpeg
f3.doc
$ ./do_ls.sh dirs
folder1
folder2
folder3
My attempt:
#!/bin/bash
#
if test $# -d file
then
echo $dirs
else (3 Replies)
I couldn't find an existing thread that addressed this question, so hopefully this isn't redundant with anything previously posted. Here goes:
I am writing a C-Shell script that runs a program that takes an arbitrary number of parameters:
myprog -a file1 \
-b file2 \
-c file3 ... \
-n... (2 Replies)
10-02-2019
