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> My generic question is: When I'm using a pipe line series of commands |
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> do I use up more/less space than doing things in sequence? |
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When you use a pipe you don't need the space to store intermediate |
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results between the two programs. Thepipe is backed by a small |
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system-allocated RAM buffer (4k under linux AFAIK) and program execution |
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is controlled according to the amount of data in the buffer. |
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Not having to save intermediate results generally means that you will |
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need less disk space: this is especially true in the mysqldump-gzip |
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example as the uncompressed dump will not be written to the disk at any |
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stage. |
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Note however (this is the "it depends" part :) that piping does not |
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affect whatever the programs might allocate or save internally: in your |
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second example (which does not involve any disk writing in either case) |
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"sort" needs to see the complete input before producing any output, so |
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it will allocate enough memory to store it whether it is invoked alone |
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or as part of a pipeline (in which case it will also stall the |
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downstream pipeline section until the upstream pipe is closed). |
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HTH, |
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andrea |
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