将单一的BAM文件，分割成每个染色体在床的格式

Please note, you must have bedtools and samtools in your $PATH environment variable or the code will not work. See wiki for additional info. The summary pretty much describes the code use. The code will index (if not already indexed) your bam file. It will then split it into chromosomes and save them in a directory you specify (defaulting to the same directory as your bam file in a folder named "chromosomes"). The files will be saved in bed format, this is the fastest way currently to do this as it does not write any bam files but instead pipes into bedtools. Designed for use on human genomes, with chromosomes 1-23 + X + Y