Right now, I am creating files to make unterminating variables. But I'm curious if there's a simpler way to create variables that don't terminate.
CodePudding user response：
I think this is a good time to be using an SQL Database. It's more scalable and functional than having a fileful of "persistent variables".
It may require a little more setup, and I admit it isn't "simpler" per say, but it will probably be worth it in the long run. You will be able to do things with your variables and that may make your future scripts simpler.
I recommend going to YouTube and find a simple instruction on how to set up a local MySQL or MSSQL. There is a guy, Mike Dane, who makes really beginner-friendly instructions. Try searching "GiraffeAcademy SQL Beginner" and see if that helps you.
CodePudding user response：
I find Redis invaluable for persisting data like this. It is a quick and lightweight installation and allows you to store many types of data:
- strings, including complete JSONs and binary data like JPEG/PNG/TIFF images - also with TTL (Time-to-Live) so data can be expired when no longer needed
- numbers, including atomic integers, floats
- lists/queues/stacks
- hashes (like Python dictionaries)
- sets, and sorted (ordered) sets
- streams, bitfields, geospatial data and esoteric hyperlogs
- PUB/SUB is also possible, where one or more machines/processes publish items and multiple consumers, who have subscribed to that topic, receive the published items.
It can also perform very fast operations on your data for you, like set intersections and unions, getting lengths of lists, moving items between lists, atomically adding/subtracting from numbers and so on.
You can also use it to pass data between processes, sub-processes, shell scripts, parent and child, child and parent (!) scripts and so on.
In addition to all that, it is networked, so you can set variables on one computer and read/alter them from another - very simply. For example, you can PUSH jobs to a queue, potentially from multiple machines, and run workers on multiple machines that wait for jobs on the queue, process them and return results to another list.
There is a discussion of the things you can store here.
Example: Store a string, then retrieve it:
redis-cli SET name fred
name=$(redis-cli GET name)
Example: Increment views of page 2 by 10, and then retrieve from different machine on network:
redis-cli INCRBY views:page:2 10
views=$(redis-cli -h 192.168.0.10 GET views:page:2)
Example: Push a value onto a list:
redis-cli LPUSH shoppingList bananas
Example: Blocking wait for next item in list - use RPOP for non-blocking:
item=$(redis-cli BRPOP shoppingList)
Also, there are bindings for Python, C/C , Java, Ruby, PHP etc. So you can "inject" dummy/test data into, or extract debug data from a running Python program using the redis-cli tool even on a different computer.
CodePudding user response：
Use environment variables to store your data.
ABC="abc"; export ABC
And the other question is, how to make environment variables persistents after reboot.
Depending on your shell, you may have different file to persist the veriables.
if using bash, run this command containing the variable's last value before reboot.
echo 'export ABD="hello"' >> $HOME/.bashrc