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Somewhat off-topic, could somebody explain why echo 3 | tee /proc/sys/vm/drop_caches rather than just echo 3 > /proc/sys/vm/drop_caches Is it because th

Somewhat off-topic, could somebody explain why echo 3 | tee /proc/sys/vm/drop_caches rather than just echo 3 > /proc/sys/vm/drop_caches Is it because the output to stdout lets you be extra sure that the right data was sent to the kernel? I'm just wondering if this is an idiom with a deeper meaning that I'm not aware of. EDIT: I'm guessing that when you run it in a script (without set -x), rather than on the command line, you can see in the log what it is you sent?

pdw 15y ago
Because you can echo 3 | sudo tee /proc/sys/vm/drop_caches but sudo echo 3 > /proc/sys/vm/drop_caches won't work.
- julian37 15y ago
  Right, that's what I was missing. That makes sense, and come to think about it, is a very useful addition to my toolbox. Thanks pdw and jochu!
- tmhedberg 15y ago
  You can also accomplish the same thing with: sudo sysctl -w vm.drop_caches=3
jochu 15y ago
Aside from reasons you mentioned, I can imagine it being because it easily allows one to add a sudo or being habit because of it. For example: echo 3 | sudo tee /proc/sys/vm/drop_caches Will allow you to write as root and sudo echo 3 > /proc/sys/vm/drop_caches Will be a permission error. It executes the echo as root and the write as the user