alt Hacker NewsMany Useless Uses of cat in this documentation. You never need to do `cat file | foo`, you can just do `<file foo`. cat is for concatenating inputs, you never need it for a single input.
Many Useless Uses of cat in this documentation. You never need to do `cat file | foo`, you can just do `<file foo`. cat is for concatenating inputs, you never need it for a single input.
As someone who worked with Unix/Linux and command line arguments for 30 years and still "abuse" cat like the documentation, I regularly hear this complaint.
Yes, "cmd <file" is more efficient for the computer but not for the reader in many cases. I read from left to the right and the pipeline might be long or "cmd" might have plenty of arguments (or both). Having "cat file | cmd" immediately gives me the context for what I am working with and corresponds well with "take this file, do this, then that, etc" with it) and makes it easier for me to grok what is happening (the first operation will have some kind of input from stdin). Without that, the context starts with the (first) operation like in the sentence "do this operation, on this file (,then this, etc)". I might not be familiar with it or knowing the arguments it expects.
At least for me, the first variant comes more naturally and is quicker to follow (in most cases), so unless it is performance sensitive that is what I end up with (and cat is insanely fast for most cases).