pipe to sudo -E bash -

Question

I was wondering what is the purpose of piping the downloaded file by curl into sudo -E bash - in the following shell:

curl -sL https://deb.nodesource.com/setup_5.x | sudo -E bash -

score 15 · Accepted Answer · edited May 23 '17 at 12:39

It's a short way of executing a script without having to save the file and then execute it. When you save the file and then execute it, a number of things can go wrong:

User didn't type the filename correctly
User didn't use the correct shell (maybe ran sh foo.sh instead of bash foo.sh)
User tried to execute the file instead of setting bash on it (./foo.sh), and forgot to set execute permissions
User forgot to use sudo

By providing a single command line to execute, the developers can decrease the number of places where things can go wrong due to luser error.

Personally, I despise piping curl to bash. It's not safe.

score 9 · Answer 2 · answered Mar 11 '17 at 07:09

9

This command would download file and attempt to execute it with root privileges.

answered Mar 11 '17 at 07:09

Barafu Albino

6,639

5

Thank you, but what is the pupose of -E option and - at the end of command ? – youssef Mar 11 '17 at 07:12
9

@Youssef -E preserves environment variables (say variables for proxy settings) and - tells bash to read commands from standard input, i.e., the pipe. – muru Mar 11 '17 at 07:13

score 2 · Answer 3 · edited Jun 05 '20 at 21:06

Agreed with @muru you should not execute some random bash script from the internet.

Better option to install NPM & Node.js is to download the binary from Download | Node.js and follow the official instructions from the Node.js project.

Unzip the binary archive to any directory you wanna install Node, I use /usr/local/lib/nodejs.

sudo mkdir -p /usr/local/lib/nodejs
# instead of XX use the version number you downloaded
sudo tar -xJvf node-XX-XX.tar.xz -C /usr/local/lib/nodejs

Open ~/.profile, add below to the end

# Nodejs
VERSION=vXX.XX.0 # <--- Put the version you downloaded
DISTRO=linux-x64
export PATH=/usr/local/lib/nodejs/node-$VERSION-$DISTRO/bin:$PATH

Refresh profile
```
. ~/.profile
```
Check if it works
```
node -v
npm version
```

pipe to sudo -E bash -

3 Answers3