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1
vote
3answers
73 views

Take a command that modifies a file inline and make it accept stdin/stdout

Let's say I have a command foo that accepts a file and performs some transformation in that file (something similar to sed -i). And let's say that this command does not accept the classic "read from ...
1
vote
1answer
581 views

Why does the factor command produce nonsense on an RSA modulus?

Ok, so I think I may have found a flaw in... something. I honestly don't know. This is such a weird scenario. I was attempting to break very small asymmetric (RSA) encryption, just as a Proof of ...
4
votes
2answers
2k views

Where can I find some good documentation for bash printf?

man printf, info printf and printf --help are all pretty useless to me; I want an explanation of the FORMAT options. For example, I could use: printf '%s\n' foo bar and get output: foo bar From ...
4
votes
1answer
5k views

Where does the “export” command come from?

Why doesn't the whereis command give any information about the export command? How does the export command work even if the shell path variable is set to null?
3
votes
3answers
705 views

Are there any utilities to quickly add, list and remove command aliases?

I'd like to be able to quickly, on-the-fly add (and list/remove) command aliases so that they persist between shell restarts (as if they were added to .bashrc). Are there any ready utilities/scripts/...
8
votes
4answers
15k views

cp or rsync, is cp really worth it?

I hope this does not count as a question without a real answer, as I can't seem to find a good reason to use cp(1) over rsync(1) in virtually all circumstances. Should one typically favour rsync over ...
11
votes
2answers
4k views

Alternative to watch which support colors

I have a command (phpunit) which has a colored output. According to the watch, command I should be able to use the --color flag to allow color rendering to pass through. However, this isn't working. ...
72
votes
4answers
21k views

What is the difference between a builtin command and one that is not?

Is there any intrinsic difference between a builtin command and another command which can nominally do the same thing? eg. Do builtins get "special" treatement? ... is there less overhead running ...