bash script to sort and index all the bam files in folder

for sample in *.sam
do
echo $sample
describer=$(echo ${sample} | sed ‘s/.sam//’)
echo $describer

# Convert file from SAM to BAM format
samtools view -b $sample > ${describer}.uns.bam

# Sort BAM file
samtools sort ${describer}.uns.bam ${describer}

# index the bam file
samtools index ${describer}.bam

# Remove intermediate files
rm ${describer}.uns.bam
done