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mchid
Asked: 2019-11-29 12:17:54 +0800 CST

glob expansion suddenly not working properly in loops

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I am trying to run:

for i in *; do sudo rm $i; done

The problem is that there is something wrong with glob expansion and I get the error:

rm: cannot remove '*': No such file or directory

I get this error for each time that the loop runs. The files are deleted (even though I used CTRL+C to stop the errors) but I am getting this error that I should not get as I did not escape the glob symbol and I did not use any single quotation marks.

This has always worked in the past without the error.

Also, if I run:

sudo rm 1*

for example, it will run use the glob properly. However, if I run:

for i in 1 2 3 4 5 6 7 8 9; do sudo rm $i*; done

I get the following:

rm: cannot remove '1*': No such file or directory
rm: cannot remove '2*': No such file or directory
rm: cannot remove '3*': No such file or directory
rm: cannot remove '4*': No such file or directory
rm: cannot remove '5*': No such file or directory
rm: cannot remove '6*': No such file or directory
rm: cannot remove '7*': No such file or directory
rm: cannot remove '8*': No such file or directory
rm: cannot remove '9*': No such file or directory

What is wrong with my globs in loops now?

I am not interested in different methods of deleting the files. I am only interested in what is wrong with glob expansion. Glob expansion seems to work (all the files are deleted) but then it wants to loop again like I escaped the glob character instead of being done.

EDIT:

It seems this is only a problem when there is an excessively large number of files. I ran the command: for i in *; do sudo rm $i; done on the same directory with only 800 files and I could not reproduce the error.

I also tested the command: for i in 1 2 3 4 5 6 7 8 9; do sudo rm $i*; done and I did not get an error when only deleting ~800 files and some numbered dummy files.

command-line bash rm

2 Answers

  1. "too many files to delete in one rm command." - is a problem with a well-known solution - use find and xargs. Together they handle "too many files" as well as "files with funny characters". Read man find and man xargs.

    Your particular case, "for i in *; do sudo rm $i; done" would be expressed as 

    find . -maxdepth 0 -type f -print0 |\
    xargs -0 --no-run-if-empty sudo rm

    will run as few sudo rm commands as it can, stuffing as many filenames as it can on a line (see xargs --show-limits </dev/null ).

    Or, one could

    sudo find . -maxdepth 0 -type f -delete

    but tastes vary.

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  2. If you need sudo to remove anything in this directory, you most certainly don’t have read permissions either, which prevents bash from performing the glob expansion – run your loop in a root shell instead:

    sudo bash -c 'for i in *; do rm "$i"; done'
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