I agree with the sentiment, but my critique applies so generally that it must be noted: if a command accepts a filename as a parameter, you should absolutely pass it as a parameter rather than `cat` it over stdin.

For example, you can write this pipeline as:

    grep '^x' foo.txt \
        | sed 's/a/b/g' \
        | awk '{print $2}' \
        | wc -l > bar.txt

This is by no means scientific, but I've got a LaTeX document open right now. A quick `time` says:

    $ time grep 'what' AoC.tex
    real    0m0.045s
    user    0m0.000s
    sys     0m0.000s

    $ time cat AoC.tex | grep what
    real    0m0.092s
    user    0m0.000s
    sys     0m0.047s

Anecdotally, I've witnessed small pipelines that absolutely make sense totally thrash a system because of inappropriate uses of `cat`. When you `cat` a file, the OS must (1) `fork` and `exec`, (2) copy the file to `cat`'s memory, (3) copy the contents of `cat`'s memory to the pipe, and (4) copy the contents of the pipe to `grep`'s memory. That's a whole lot of copying for large files -- especially when the first command grep in the sequence usually performs some major kind of reduction on the input data!