The codes I entered are as follows:
qiime tools import **
--type 'SampleData[SequencesWithQuality]' **
--input-path /home///manifestfile1.txt **
--output-path single-end-demux.qza **
--input-format SingleEndFastqManifestPhred33V2
qiime demux summarize **
--i-data single-end-demux.qza **
--o-visualization single-end-demux.qzv
qiime cutadapt trim-single
--i-demultiplexed-sequences single-end-demux.qza
--p-adapter CCATCTCATCCCTGCGTGTCTCCGACTCAG
--p-front CCTCTCTATGGGCAGTCGGTGATGTGCCAGCMGCCGCGGTAA
--p-error-rate 0.1
--o-trimmed-sequences trimmed-seqs.qza
--verbose
qiime demux summarize
--i-data trimmed-seqs.qza
--o-visualization trimmed-seqs.qzv
qiime dada2 denoise-pyro **
--i-demultiplexed-seqs trimmed-seqs.qza **
--p-trim-left 15 **
--p-trunc-len 240 **
--o-representative-sequences rep-seqs-dada2.qza **
--o-table table-dada2.qza **
--o-denoising-stats stats-dada2.qza
qiime metadata tabulate **
--m-input-file stats-dada2.qza **
--o-visualization stats-dada2.qzv
mv rep-seqs-dada2.qza rep-seqs.qza
mv table-dada2.qza table.qza
qiime feature-table summarize **
--i-table table.qza **
--o-visualization table.qzv
qiime feature-table tabulate-seqs **
--i-data rep-seqs.qza **
--o-visualization rep-seqs.qzv
qiime feature-classifier classify-sklearn **
--i-classifier gg-13-8-99-515-806-nb-classifier.qza **
--i-reads rep-seqs.qza **
--o-classification taxonomy.qza
qiime metadata tabulate **
--m-input-file taxonomy.qza **
--o-visualization taxonomy.qzv
qiime taxa barplot **
--i-table table.qza **
--i-taxonomy taxonomy.qza **
--o-visualization taxa-bar-plots.qzv
qiime tools export
--input-path table.qza
--output-path table
biom convert
--to-tsv
-i feature-table.biom
-o feature-table.tsv
I ran these codes twice for the same set of samples. The "feature-table.tsv" I obtained is not the same.