4. A region should be presented in one of the following formats:\n\
`chr1', `chr2:1,000' and `chr3:1000-2,000'. When a region is\n\
specified, the input alignment file must be an indexed BAM file.\n\
+\n\
+ 5. Option `-u' is preferred over `-b' when the output is piped to\n\
+ another samtools command.\n\
\n");
return 1;
}