# --p-trim-left and --p-trunc-len error

Hi, i had been stucked here for hours now, gone through lots of same issues but doesn't seem to fix mine. here is my command and the error.
--i-demultiplexed-seqs demux.qza
--p-trim-left-f 20
--p-trim-left-r 20
--p-trunc-len-f 295
--p-trunc-len-r 234
and comes with these errors
(1/4?) no such option: --p-trim-left-f Did you mean --p-trim-left?
(2/4?) no such option: --p-trim-left-r Did you mean --p-trim-left?
(3/4?) no such option: --p-trunc-len-f Did you mean --p-trunc-len?
(4/4?) no such option: --p-trunc-len-r Did you mean --p-trunc-len?
i have carefully typed the command to make sure i use the appropriate dash lines, yet i get same errors. please any suggestion?

Hi @pyghost,
I made this post public as this is the preferred method for asking for help on the QIIME 2 forum instead of DMs.

The error message here is actually being really nice and suggesting the correct syntax.
Your syntax = `--p-trim-left-f`, what it should be `--p-trim-left`, notice the `-f` differences here.
Now, I also noticed that you are providing reverse read parameters, however, your command is calling the `denoise-single` action, which actually does not have any reverse parameters.
Assuming you have pared-end data, I recommend typing `qiime dada2 denoise-paired --help` for the appropriate parameter syntax to use.

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ok, great. sorry about that. Thanks for the assistance.

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