linux command learning and use record

1. File batch rename: rename all .xml files to .txt, the first parameter is the string in the file name, the second parameter is the replaced file name, and the third is the current directory file list
rename .xml .txt *.xml
2. The decompression does not display the process: v means the display process, if it is removed, it will not be displayed.
tar zxvf file.tar.gz