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Let say I have the program: 

Calculate.py

Is there a unix command-line that counts the number of lines outputted from my program, Calculate.py?

MEhsan
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2 Answers2

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You can pipe the output in to wc. You can use the -l flag to count lines. Run the program normally and use a pipe to redirect to wc.

python Calculate.py | wc -l

Alternatively, you can redirect the output of your program to a file, say calc.out, and run wc on that file.

python Calculate.py > calc.out
wc -l calc.out
cutrightjm
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    It's little things like this that make piping so damn powerful. We'd do ourselves good to bring this interoperability back to software development, which I suppose is what Functional Programming is all about. – Joshua Pinter Oct 27 '18 at 14:26
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    @JoshuaPinter on the other thand if you just want to pipe the number of lines into another function, you now need to manually parse the output of `wc`. Mercifully this is easy (`cut -f1 -d' '`), but the same isn't true for every command. There's something to be said for the Powershell approach of making the command line primitive an "object", rather than a text stream. – shadowtalker Nov 26 '18 at 19:42
  • @shadowtalker I'm not familiar with Powershell but passing `object`s instead of `String`s makes sense. At some point I'd like to dive deep into more command line tooling. – Joshua Pinter Nov 27 '18 at 02:13
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Above communicate (wc -l) will count the empty lines too. so better to use below command which deletes the empty lines and count it

python Calculate.py |sed '/^$/d'| awk '{print NR}'| sort -nr| sed -n '1p'
Praveen Kumar BS
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    Seriously?  ```sed | awk | sort | sed``` just to count lines?  (1) `sed '/^$/d'` can be collapsed into `grep -v '^$'` or even `grep '.'`.  (2) Then, to count lines, add `-c`, so `python Calculate.py | grep -c '.'`.  (And you don’t even need the quotes around “**`.`**”.) – G-Man Says 'Reinstate Monica' Mar 15 '22 at 20:47