[galaxy-user] Extracting number of reads from Bowtie analysis

Hello, I am new here! I am aligning Solexa files to genome using tool: NGS: Mapping: Map with Bowtie for Illumina. My question: What is the most easy way to check the number of aligned reads in the output from above? I couldn't find this number directly. I found a way, but it looks circular and unoptimal: to run Bowtie with option: put umapped reads into the file, download the file, open it, count reads, subtract from reads in the original file. However, downloading large files is time-consuming, and I am sure the easier way is somewhere. Further question: good link to help on how to improve number of reads from ChIP study aligned to mouse genome would be also appreciated. best regards, Jerzy