Combine time and dd commands to test memory speed under Linux

In Linux, the "time" and "dd" commands are two independent commands that can be used together to measure the execution time of the "dd" command.

Here is a brief description of them:

1. time command:

   • The "time" command is used to measure command execution time and resource usage.
   • It can accurately calculate the execution time of the command, including actual execution time, CPU time, system time and memory usage, etc.
   • The syntax of the time command is as follows:time command
     • "command" is the name of the command or program to be executed.
   • Example:
     • Measure the execution time of the "ls" command:time ls

2. dd command:

   • The "dd" command is a powerful data conversion and copy command, usually used to copy files, devices and data streams.
   • It copies data from the input source to the output destination based on the specified block size and count value.
   • The syntax of the dd command is as follows:dd [options]
     • Some commonly used options include:
       • "if": Specifies the input source (input file or device).
       • "of": Specifies the output destination (output file or device).
       • "bs": Specifies the block size.
       • "count": Specifies the number of blocks to copy.
   • Example:
     • Copy files:dd if=inputfile of=outputfile
     • Copy device:dd if=/dev/input of=/dev/output

Using the "time" and "dd" commands together, you can measure the execution time of the "dd" command. You can add the "time" command before the "dd" command to calculate the execution time of the "dd" command

For example:

time dd if=inputfile of=outputfile

This will execute the "dd" command and display its execution time and other relevant information.

Note that "time" may be a built-in command in some Linux distributions and an external executable in others. You can use the "which time" command to determine the location of the "time" command on your system.