I have the following variable in bash: $httpd_server_count, this variable can contain values like 1 or 2 and etc. And depending on this value I need to get proper value in $settings variable. The string is:
If the $httpd_server_count=1:
settings={'httpd1': {'server': 'settings.server1'},
If the $httpd_server_count=2:
settings={'httpd1': {'server': 'settings.server1'}, {'httpd2': {'server': 'settings.server2'},
and count can be is up to 10 and more. How to properly organize it in code?
I'm a bit unclear on what you are needing, but it appears you want to read the value of httpd_server_count and based on the number 1, 2, whatever generate the server strings needed. If I have it right, one way would be to use a simple C-Style for loop based on httpd_server_count. For example:
#!/bin/bash
str=
for ((i = 1; i <= $httpd_server_count; i++)); do
str="${str}{'httpd$i': {'server': 'settings.server$i'}, "
done
echo -e "str\n\n$str"
You would still be responsible for trimming the trailing , and appending a closing '}' if required. But, if your value of httpd_server_count is 1, then you get:
{'httpd1': {'server': 'settings.server1'},
If it is 2, you get:
{'httpd1': {'server': 'settings.server1'}, {'httpd2': {'server': 'settings.server2'},
This may give you an idea you can run with. Let me know if you have any questions. (by the way, a json parser is generally preferred, like jq)
++ would have done the same way! Not posting it as a separate one. BTW using an array would slightly look neater. But a proper JSON tool would be the ideal way.Use functions in bash to make the code more portable and efficient. Just put the code in a wrapper like below. Logic is similar to this David C. Rankin's answer,
function settingsGenerator() {
local httpd_server_count=$1
local i
local settings
for ((i=1; i<=httpd_server_count; i++))
do
settings="${settings}{'httpd$i': {'server': 'settings.server$i'}, "
done
printf "%s" "$settings"
}
and store the output of the function in a variable, settings as
settings=$(settingsGenerator 2)
printf "%s\n" "$settings"
{'httpd1': {'server': 'settings.server1'},{'httpd2': {'server': 'settings.server2'},
Using arrays would require a small change something like,
function settingsGenerator() {
local httpd_server_count=$1
local i
local settings=()
for ((i=1; i<=httpd_server_count; i++))
do
settings+="{httpd$i': {'server': 'settings.server$i'}, "
done
printf "%s" "${settings[@]}"
}
Use for loop:
#!/bin/bash
for i in `seq $httpd_server_count`; do
settings+="{'httpd$i': {'server': 'settings.server$i'}, "
done
In the context where an assignment statement is assigning a value to a shell variable or array index, the += operator can be used to append to or add to the variable's previous value. This includes arguments to builtin commands such as declare that accept assignment statements (declaration commands). [...] When += is applied to an array variable[...]