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    <p>You're looking at this the wrong way, I think. Awk's <code>system</code> just takes any old string, so give it one, e.g.:</p> <pre><code>system("echo " var); # see side note below </code></pre> <p>(remember that in awk, strings are concatenated by adjacency). Moreover, <code>system</code> just runs a command; to capture its output, you need to use <code>getline</code>, similar to your question #1.</p> <p>If you want to read all the output of <code>ls</code> you need to loop over the result from <code>getline</code>:</p> <pre><code>awk 'BEGIN { while ("ls" | getline var) print "I got: " var; }' </code></pre> <p>Since this defines only a <code>BEGIN</code> action, <code>awk</code> will start up, run <code>ls</code>, collect each output line and print it, and then exit.</p> <hr> <p>Side note: be very careful with variables passed to a shell (this includes both calls to <code>system</code> and items on the left hand side of <code>| getline</code>, plus some other cases in modern varieties of <code>awk</code>—anything that runs a command). Backquotes, <code>$(command)</code>, and semicolons can all allow users to invoke arbitrary commands. For instance, in the <code>system("echo " var)</code> example above, if <code>var</code> contains <code>; rm -rf $HOME</code> the command becomes <code>echo ; rm -rf $HOME</code>, which is almost certainly not something you want to have happen.</p> <p>You can check for "bad" characters and either object, or quote them. Modern 8-bit-clean shells should only require quoting quotes themselves (for syntactic validity), <code>$</code>, <code>&lt;</code>, <code>&gt;</code>, <code>|</code>, and <code>`</code>. If you use single quotes to quote arguments (to make them appear as a single "word"), you need only escape the single quotes. See <a href="https://unix.stackexchange.com/a/64218">this unix.stackexchange.com answer</a> for more details.</p> <hr> <p>One other side note: I tend to add "unnecessary" semicolons to my awk scripts, making them look more like C syntactically. Old habit from decades ago.</p>
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    1. POAWK - Transmission of a variable with getline to system ()?
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    1. COtorek: Thank you for your response. For this application, you can not assign a variable output from system ()? As in this example: `awk 'BEGIN {var="ls -l"; system(var); print var}'`
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    2. COThe `system` function: (1) runs something to completion; then (2) returns its exit value. `ls` has an exit value of 0 on success. So, you can do `x = system(foo); print "ran " foo " and got " x;` for instance. If `foo` is the string `"ls"`, this will run `ls` with output going to awk's stdout, and set `x` to 0 because `ls` will succeed.
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    3. COThank you for your response.
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