Invalid arguments or "--filename argument must contain one '{}'" on split function about qsv

[jqnatividad]

Hi @papagunit,

You'll need to specify the <outdir> parameter for it to work, i.e.:

qsv split myoutdir -s 300 --filename Test{}.csv '\.Filename.csv'

Regardless, I'll improve the usage text with examples rather than linking to the tests, and add explicit error handling if the outdir arg is empty.