Batch rename in linux using awk

In linux, awk is used to rename the name of the designer in batches to send a lot of portraits Mxxxx.png, male headers, FXXXX.png female portraits. The file name I need is www.2cto.com.
Ic_male_head0xxxxx ic_female_head0xxxxx must be renamed. Manually rename the name, too earthy. Use AWK to save the following code as iconRename. sh :#! /Bin/sh ls F * M * | awk www.2cto.com '{first = substr ($1, 1, 1); suffix = substr ($1, 2 ); if (first = "M") {newfile = "ic_male_head0" suffix;} else {newfile = "ic_female_head0" suffix ;} system ("mv" $1 "" newfile);} 'by Han Gong