Samtools can be used to convert between sam and bam:
-b
indicates that the input file will be in BAM format-S
indicates that the stdout should be in SAM formatsamtools view -sB thing.bam > thing.sam
And to convert between sam and bam:
samtools view thing.sam > thing.bam
samtools sort thing.bam thing
samtools index thing.bam
This will produce a sorted, indexed bam. This will create the files thing.bam
and thing.bam.bai
. To use a bam you must have an index file.