The Definition of Verbose Output

Many Linux commands support a -v switch that, in many cases, offers additional context and information compared to the standard output of that program.

A simple example is the ps command that returns a list of active processes.

ps

The above command lists processes on the system and the output from the command is as follows:

• PID (process ID)
• TTY (terminal type)
• Time
• CMD (command)

The ps command accepts the -v switch, which shows verbose output.

ps -v 

The above command still shows every process but now you see the following columns:

• PID
• TTY
• STAT
• TIME
• MAJFL
• TRS
• DRS
• RSS
• %MEM
• COMMAND

Generally, you only want to use a verbose switch if there is extra information that you really need to see and it shouldn't be used for every command you use. Indeed not every command has an option to show verbose output.

The reason for not showing verbose output is that it slows down the command slightly so it isn't something you want to use inside scripts unless you specifically need to output extra information.