Creating array of objects in bash - bash

Question

Is it possible to create an array of objects in bash?
That's how I'm trying:
declare -a identifications=(
{
email = '...',
password = '...'
}
)
declare -a years=(
'2011'
'2012'
'2013'
'2014'
'2015'
'2016'
)
for identification in "${identifications[#]}"
do
for year in "${years[#]}"
do
my_program --type=CNPJ --format=XLS --identification=${identification.email} --password=${identication.password} --competence=${year} --output="$identification - $year"
done
done
Obviously, this doesn't work, and I'm not finding how to achieve that, since I'm not finding bash objects.

Answer 1

You could do some trickery with associative arrays (introduced in Bash 4.0) and namerefs (see manual for declare and the first paragraph of Shell Parameters – introduced in Bash 4.3):
#!/usr/bin/env bash
declare -A identification0=(
[email]='test#abc.com'
[password]='admin123'
)
declare -A identification1=(
[email]='test#xyz.org'
[password]='passwd1!'
)
declare -n identification
for identification in ${!identification#}; do
echo "Email: ${identification[email]}"
echo "Password: ${identification[password]}"
done
This prints
Email: test#abc.com
Password: admin123
Email: test#xyz.org
Password: passwd1!
declare -A declares an associative array.
The trick is to assign all your "objects" (associative arrays) variable names starting with the same prefix, like identification. The ${!prefix#} notation expands to all variable names starting with prefix:
$ var1=
$ var2=
$ var3=
$ echo "${!var#}"
var1 var2 var3
Then, to access the key-value pairs of the associative array, we declare the control variable for the for loop with the nameref attribute:
declare -n identification
so that the loop
for identification in ${!identification#}; do
makes identification behave as if it were the actual variable from the expansion of ${!identification#}.
In all likelihood, it'll be easier to do something like the following, though:
emails=('test#abc.com' 'test#xyz.org')
passwords=('admin123' 'passwd1!')
for (( i = 0; i < ${#emails[#]}; ++i )); do
echo "Email: ${emails[i]}"
echo "Password: ${passwords[i]}"
done
I.e., just loop over two arrays containing your information.

Answer 2

I tend to use json to create objects. For me it makes it really easy and flexible.
Here is a oversimplified example.
I create a json file: devices.json
{
"backup" : [{
"addr":"192.168.1.1",
"username":"backuper",
"dstfile":"firewallconfig",
"ext":".cfg",
"method":"ssh",
"rotate":"no",
"enabled":"yes"
}, {
"addr":"192.168.1.2",
"username":"backuper",
"dstfile":"routerconfig",
"ext":".cfg",
"method":"ssh",
"rotate":"no",
"enabled":"yes"
}]
}
Bash script: task.sh
# read the devices.json file and store it in the variable jsonlist
jsonlist=$(jq -r '.backup' "devices.json")
# inside the loop, you cant use the fuction _jq() to get values from each object.
for row in $(echo "${jsonlist}" | jq -r '.[] | #base64'); do
_jq()
{
echo ${row} | base64 --decode | jq -r ${1}
}
echo "backing up: $(_jq '.addr')"
echo "using method: $(_jq '.method')"
Done
The guy who posted the original post can be found by googling "using json with bash" or something.