What is the difference between internal command and external command in Linux?

Linux Shell Command Problem , Please Help?

• In linux Shell Command i want to : 1)Make a A directory create four text files a, b, c and d, each containing ID of one of our group member : for example for text file ID is a : 6678 , for b : 6679, for C :6680 2)Find all files in my home directory (in Linux command line type echo $HOME which will tell you which is your home directory) which contain only selected student ID. 3) Merge all the source text files I created in 1) into one text file containing all the details about my group members. Please tell me the Linux Shell Command for these 3 problems.

• Answer:

  Your answers can be found here grasshopper http://ss64.com/bash/