curl - NodeJS install on Ubuntu -

i've installed nodejs on ubuntu, followihg instructions node site. went ok, kind of confused have done.

i enterred following 2 commands:

curl -sl https://deb.nodesource.com/setup_4.x | sudo -e bash - sudo apt-get install -y nodejs 

the second 1 clear me. first command do?

curl command-line tool transfer data using urls. in case making request https://deb.nodesource.com/setup_4.x.

the -l option (if read the curl manual page) means if server responds redirect, curl try new location.

the -s option means curl should silent, , not print errors or progress or other informational messages.

the data curl receives printed on standard output.

this output piped input sudo -e bash - command. sudo command runs specified command superuser root. option -e tells sudo preserve environment (e.g. $path environment variable etc.).

the command sudo runs bash -, standard linux shell. trailing dash (-) tells bash should run login shell. bash command read standard input , execute normal shell commands.

so whole line does, download shell-script https://deb.nodesource.com/setup_4.x , use input shell execute superuser privileges.