Why `sudo echo "..." > file` Doesn’t Work — and How to Fix It

Tried this command:

echo "/export  *(rw,async,no_root_squash,no_subtree_check)" > /etc/exports

But the file didn’t get updated.

Core Issue: Redirection (>) Happens Before sudo

When executing

sudo echo "line" > /etc/file

Only the echo runs with sudo. So this fails silently (or leaves the file empty).

Correct Approach: Use sudo tee

echo "/export  *(rw,async,no_root_squash,no_subtree_check)" | sudo tee /etc/exports > /dev/null

This works because:

• echo runs normally
• Output is piped (|) to sudo tee
• tee runs with root privileges and writes the file

IMPORTANT: Append Instead of Overwrite?

Use tee -a:

echo "another line" | sudo tee -a /etc/exports > /dev/null

What I Did (and Why It Went Wrong)

Ran:

echo "/export ..." > sudo tee /etc/exports > /dev/null

This:

• Created a file named sudo in your current directory (with the NFS export line in it)
• Did not invoke the sudo command

Summary