Re: curl -fsSL someurl | sh
Not if that exe was basically running its own curl to get the real code. A lot of installers work that way, and although they're not my favorite, they think there is a reason because it lets people install the subset of components without, for example, including the translations and fonts for a bunch of languages the user doesn't want in the initial file. Malware can easily use a basic downloader which won't look dodgy until the specific sample has been reported, and it just downloads the more suspicious code and executes it from memory.
Installing this program on Linux (or anything else) will involve one of two things:
1. Downloading a binary from someone else's server and executing it.
2. Downloading a rather large chunk of code and compiling it.
And running it involves one more:
3. Downloading a model, either from their server or another one, and running it.
That's three methods to run malicious code if they are malicious. Saving the script and reading through it won't help you when this line from the real script
curl --fail --show-error --location --progress-bar -o $TEMP_DIR/ollama "https://ollama.com/download/ollama-linux-${ARCH}${VER_PARAM}"
Can download any binary. If they're doing something malicious, the malicious part would be in that file, not this script which I can read in a minute. If you don't trust them, you can try to build from source instead, but I somehow doubt you're reading every file to make sure you don't think anything in it is malicious.