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On Sunday, July 17 at 17:47 (-0700), Grant said: |
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> ran this and the output was voluminous but looked good: |
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> |
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> /usr/bin/find /home/user -type f -name "*-`/bin/date -d 'yesterday' |
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> +\%Y\%m\%d`*.jpg" |
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> |
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> So I ran it again, adding -delete right before -type. After a lot of |
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
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That was a mistake. |
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> processing I got a line of output like this for each file: |
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> |
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> /usr/bin/find: `/home/user/1-2011071612345.jpg': No such file or |
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> directory |
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> |
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> Unfortunately the command actually deleted the entire /home/user |
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> folder. Can anyone tell me what went wrong? Maybe '/home/user' was |
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> at the very top of the long list that scrolled up the screen when I |
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> ran the find command without -delete? |
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> |
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Well this is an unfortunate way to learn how find works. A better way |
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would be: |
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$ man find |
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Basically find works of a chain of selection criteria. It crawls all |
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the files/dirs and when one item in the chain is true for the criteria, |
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it checks for the other. For example |
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$ find /path -type f -name blah -print |
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Crawls /path, for each file/dir it checks if it is a regular file (-type |
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f), if that is true, it checks if it's name is "blah", if that is true, |
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it prints the name (blah). |
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Therefore, |
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$ find /path -delete -type f -name .... |
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Crawls path, then checks "-delete".. but wait, -delete evaluates to |
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"true if removal succeeded" (find(1)), so it deletes the file, then |
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checks to see if it is a regular file, then if that is true then it |
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checks the name... but all that doesn't matter because your files are |
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deleted. |
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You should never put -delete at the beginning of a chain and, arguably, |
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you shouldn't use -delete at all. It even says in the man page: |
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Warnings: Don't forget that the find command line is evaluated |
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as an expression, so putting -delete first will make find try to |
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delete everything below the starting points you specified. When |
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testing a find command line that you later intend to use with |
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-delete, you should explicitly specify -depth in order to avoid |
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later surprises. Because -delete implies -depth, you cannot |
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usefully use -prune and -delete together. |
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