我为什么不能在/ etc /中sudo回显一行？

Question

I am on centos and I did sudo echo 'testline'>>/etc/test/test it said -bash: /etc/test/test: Permission denied

However, when I do sudo vi /etc/test/test and insert testline and do :wq it writes out fine, why is this happening?

Answer 1

You need to wrap the whole statement (including the redirect) into a group so the sudo extends around it.

sudo bash -c "echo 'testline' >> /etc/test/test"

Note: that, too, will fail if /etc/test doesn't exist yet.

Answer 2

The redirection is processed by the shell prior to running sudo , rather than being part of it. Use tee instead so that sudo runs the process that actually opens the file for writing.

echo 'testline' | sudo tee -a /etc/test/test > /dev/null

Answer 3

这些人已经介绍过的相同一般解决方案的另一种语法：

echo "echo 'testline'>>/etc/test/test" | sudo su