head: illegal line count on MacOS

[wodow]

A error from head appears with first use:

$ rgr foo -R bar
ACTUAL CONTENT WILL BE REPLACED IN YOUR FILESYSTEM.
If you'd like to do a dry-run instead, cancel the program and run with '-r' instead of '-R'.
Are you sure you'd like to continue? (Y or y to continue; any other key or just Enter to exit) y
head: illegal line count -- -9


real	0m0.037s
user	0m0.009s
sys	0m0.030s

This is using ripgrep v13 on MacOS 13.5.2.

[ElectricRCAircraftGuy]

@wodow, does rg foo -r bar work for you? It does a dry run replacement without my wrapper.

I need to know for certain whether the problem is with ripgrep or with my rgr wrapper.

[wodow]

Yes, the dry run feature works ok.

I will try to debug by stepping through the script when next at a terminal.

[ElectricRCAircraftGuy]

Before running the script, run set -x to turn on terminal command echo. When done, run set +x to turn it back off. Copy and paste the results so I can see which command is failing.

Also, try running other benign rg commands using rgr instead, to see if any other commands through my wrapper fail.

[wodow]

I'm not sure set -x is sufficient. It doesn't reveal anything new:

$ set -x
$ rgr foo -R bar
+ rgr foo -R bar
ACTUAL CONTENT WILL BE REPLACED IN YOUR FILESYSTEM.
If you'd like to do a dry-run instead, cancel the program and run with '-r' instead of '-R'.
Are you sure you'd like to continue? (Y or y to continue; any other key or just Enter to exit) y
head: illegal line count -- -9


real	0m0.031s
user	0m0.019s
sys	0m0.065s

still not tried stepping through -- will get to it

[wodow]

Is the problem as simple as POSIX standard head doesn't take negative numbers? See e.g. https://stackoverflow.com/a/60336903

[wodow]

On MacOS, GNU head is available from Homebrew, and by default installs as ghead. This accepts a negative num param, so replacing head in the script with ghead fixes the problem.