Bash function argument unexpectedly interpreted as file/directory

Question

I created a function in my .bashrc file to print the top N files/directories in the working directory:

# .bashrc
function topN () { du -hs * | sort -rh | head -"$1"; }

However, sourcing my .bashrc and then running topN 5 returns:

head: cannot open '5' for reading: No such file or directory

I have attempted various quoting methods and combinations, with generally the same error. How can I re-write this function to treat the argument 5 as a value rather than a file/directory?

Simply running du -hs * | sort -rh | head -5 returns the expected listing of the top 5 files/directories and their sizes.

I am not able to reproduce the issue. If you call it as `topN 6` does the error message change? Make sure you are using the current version of your function (declare -f topN). Run `du -hs * > du.txt` and update question with said data (run your program in a sub-directory to ensure it only has information you care to have public). — Allan Wind, Sep 10 '22 at 02:48
You would get this error if `$1` contained a space. How are you calling the function? — Allan Wind, Sep 10 '22 at 02:51
Interestingly, naming the function `topN` works, but `topn` produces the error. — IslandPatrol, Sep 10 '22 at 02:53
@IslandPatrol hmm... makes no difference here (either works). — Allan Wind, Sep 10 '22 at 02:54
Indeed, that was the issue. Apparently my shell had a stale alias with that name. Thanks for the help! Problem resolved. — IslandPatrol, Sep 10 '22 at 02:57
Consider changing $1 to ${1:-5} or whatever you use most. Makes these kinds of scripts easier to live with. — Allan Wind, Sep 10 '22 at 03:03
Good general tip. In this case, `head` returns a default of 10 entries, which is reasonable for my use case. — IslandPatrol, Sep 10 '22 at 03:09
It does no find/show hidden files though, files/directories that starts with a `.` — Jetchisel, Sep 10 '22 at 03:43
Hidden files and directories can be accounted for by omitting the `*` and substituting `-a` in place of `-s`: `du -ha | sort -rh` — IslandPatrol, Sep 10 '22 at 04:03

score 1 · Accepted Answer · answered Sep 10 '22 at 02:57

1

You were running a (stale) alias rather than the function you shared with us.

answered Sep 10 '22 at 02:57

Allan Wind

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Note that by adding an answer and having it upvoted or accepted, you blocked the OP from deleting their own question. For a question that's off-topic (in this case, eligible for close on acount of being "resolved in a way unlikely to help other users"), that's poor form. – Charles Duffy Sep 10 '22 at 02:59
Shall I un-accept the answer @CharlesDuffy? – IslandPatrol Sep 10 '22 at 03:01
@CharlesDuffy hmm... root cause was: I thought that I was doing x but actually doing y. This is debugging 101. Makes no difference to me. It usually annoys me when people delete their question after I answered it (only they derived value of my effort instead of the larger community). – Allan Wind Sep 10 '22 at 03:10
@CharlesDuffy you mentioned "you blocked the OP from deleting their own question". However, there is a [Delete question] link presented at the top of my screen. Unless this is a case of poor UI design, it appears that I could, in fact, delete the question. – IslandPatrol Sep 10 '22 at 03:13
@IslandPatrol, if you don't have enough reputation points it won't let you do that if the question is open and has an upvoted answer. (That's a deliberate design decision, because we've long had a problem with students asking questions to support their homework, then deleting them to hide evidence of academic dishonesty after receiving an answer). If it's being permitted for you right now, I suspect that's likely on account of the question being closed (or perhaps the threshold below which that rule applies is much lower than I remember). – Charles Duffy Sep 10 '22 at 23:46

Bash function argument unexpectedly interpreted as file/directory

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