"Linux" about the use of minus sign-

Pipeline commands are quite important in Bash's continuous processing program! In addition, in the analysis of log file is also a very important link, so please pay special attention! In addition, in the pipeline command, often using the stdout of the previous command as the stdin, some commands need to use the file name (for example, tar) for processing, the stdin and stdout can use the minus "-" to replace, for example:

Tar Tar -xvf-

The above example says, "I'll pack the files from home/home, but the packaged data is not recorded to the file, but to the stdout; after the pipeline, TAR-CVF-Home is routed to the back TAR-XVF-". The following-is the stdout of the previous command, so we don't need to use file! This is a very common example! Pay attention!

　Reference:http://vbird.dic.ksu.edu.tw/linux_basic/0320bash.php#pipe_7