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  1. PO
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    <p>The other answers cover your real problem. But one thing worth saying more about is how <code>$*</code> and <code>$@</code> differ in expansion when double quoted. <strong>tl;dr</strong> You almost always want <code>"$@"</code>.</p> <p><code>"$*"</code> expands to <strong>a single string</strong> containing all the parameters with the first character of <code>IFS</code> in between them. In practice this usually means all params as one string separated by spaces. So if your params are <code>file1.txt</code>, <code>file2.txt</code> and <code>file3.txt</code>, then <code>"$*"</code> hands that to the loop as <strong>one thing</strong>, namely <code>file1.txt file2.txt file3.txt</code>. That one thing, of course, does not exist as such.</p> <p><code>"$@"</code> expands to <strong>each of the parameters</strong>, one at a time, treated as a single "word". This is good because it will treat <code>file1.txt</code>, <code>file2.txt</code> and <code>file3.txt</code> from the earlier example correctly as <strong>three items</strong>. The loop will receive them correctly one at a time. In addition, <code>"$@"</code> is good since even if your filenames have spaces in them, you will get the right behavior since the loop will handle, e.g. <code>filename 1</code>, <code>filename 2</code>, <code>filename 2 and a half</code> as three items, one by one. (Normally the shell treats a space as marking the end of a word, so <code>filename 1</code> would look like <strong>two items</strong> to the shell, <code>filename</code> and <code>1</code>.</p> <p>When they aren't quoted both <code>$@</code> and <code>$*</code> expand the words of all the positional parameters. So in that case, they are effectively identical (and both a bad idea since they don't protect you from oddly named files).</p> <p>There's a good visualization of all possibilities here: <a href="http://wiki.bash-hackers.org/scripting/posparams#mass_usage" rel="nofollow">http://wiki.bash-hackers.org/scripting/posparams#mass_usage</a>.</p>
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    1. PObash script: looping over arguments
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    1. USTelemachus
    1. USTelemachus
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      1. VTUpMod
    1. COI think you should include the double quotes in your answer since the two variables also have meaning (identical meanings, in fact) when unquoted. You might also want to cover the unquoted meanings in the answer. As it stands: _`$*` expands to a single string_ is incorrect; it should be _`"$*"` expands to a single string_ ... Yes, you mentioned double quotes in the previous paragraph, but omitting them in the next is misleading.
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      1. USJonathan Leffler
    2. CO@JonathanLeffler You're absolutely right. Not sure what's wrong with me. I should include the quotes, and I'll mention the unquoted versions.
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      1. USTelemachus
    3. COHey telemachus. I had a feeling "$*" did expand to a single string, thanks for confirming and explaining what was happening behind the scenes.
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      1. USPaolo
 

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