UNIX Directory Creation with mkdir

The $mkdir$ command in UNIX is used to create directories. It can accept multiple arguments to create several directories at once.

Command Breakdown

The question requires creating a parent directory named 'PIS' and then two subdirectories, 'progs' and 'data', inside 'PIS'. The command must handle this structure correctly.

Option Analysis

• Option 1: $mkdir PIS/progs PIS/data PIS$
  This command attempts to create subdirectories before the parent directory 'PIS' exists. This will likely result in an error unless the parent directory is already present.
• Option 2: $mkdir PIS progs data$
  This command creates three separate directories ('PIS', 'progs', 'data') in the current working directory, not 'progs' and 'data' inside 'PIS'.
• Option 3: $mkdir PIS PIS/progs PIS/data$
  This is the correct command. It first creates the directory 'PIS'. Subsequently, it creates the subdirectories 'PIS/progs' and 'PIS/data' within the just-created 'PIS' directory.
• Option 4: $mkdir PIS/progs data$
  This command attempts to create 'PIS/progs' (which requires 'PIS' to exist first) and 'data' in the current directory. It fails to create 'PIS' itself and the 'PIS/data' subdirectory.
• Option 5: (Empty)
  This option is invalid.

Conclusion

Option 3 successfully creates the required directory structure by first making the parent directory and then the subdirectories within it.