Running command for bash in fish shell

Question

I'm trying to identify all the large files in my git repo history and came across this command posted here.

git rev-list --objects --all \
| git cat-file --batch-check='%(objecttype) %(objectname) %(objectsize) %(rest)' \
| sed -n 's/^blob //p' \
| sort --numeric-sort --key=2 \
| cut -c 1-12,41- \
| $(command -v gnumfmt || echo numfmt) --field=2 --to=iec-i --suffix=B --padding=7 --round=nearest

I've been trying to figure out how to run this in a fish shell on a mac (For mac, you need to brew install codeutils to be able to run the last line). The error I'm getting is fish: Illegal command name '$(command -v gnumfmt || echo numfmt)'. I tried removing the $ sign got the same error (without the dollar sign though).

I'm a pretty new fish shell user, so would love some help from more experienced users. For now, I'm just switching to bash to run the script but it would be nice not to have to do that.

Answer 1

Fish 3.0 lets you use variables (see https://github.com/fish-shell/fish-shell/issues/154). So you could do this indirectly:

set cmd (command -v gnumfmt || echo numfmt) 
git rev-list ... | $cmd ...

For fish 2.x define a fish function that runs the appropriate command; e.g.,

function numfmt
    if command -q gnufmt
        gnumfmt $argv
    else
        command numfmt $argv
    end
end

Answer 2

Apparently fish does not support command substitution in the command position. But since here it is used just to find out if the numfmt or gnumfmt command is available, you should be able to just use the correct command name for your system (as installed by brew) instead of the whole $(...) substitution.