Question

COSC 3411 /ITAP 3411 Homework (UNIX Shell Commands)

1. How would you ensure that all ordinary files created by you have rw-rw---- as default permissions?

2. How would you sort in the background a file called "bad.txt", and place the results in a file called "sort.txt"?

3. Archive the contents of your home directory (including any subdirectories) using tar. Compress the tar archive with gzip. Now extract their contents.

4. Use the “find” command to locate in /docs and /usr/docs all files that
   1. Begin with z and have the extension .txt or .c
   2. Move the above found files (in question a) to /tmp/TXTandCFiles directory

5. Type umask 000 and then create a file called world.txt containing the words "hello world". Look at the permissions on the file. What's happened? Now type umask 022 and create a file called world2.txt.

6. Use find to display the names of all files in the /home subdirectory tree. Can you do this without displaying errors for files you can't read?

Answer 1

The default permission to a file is controlled by the user mask and this user mask can be set using the umask command in the initialization file and for the file to have rw-rw---- as default permissions you need to assign the umask value as 007 where the first 0 indicates the read and write permission to the user and second 0 indicates the read and write permission to the group and 7 indicates no permission to the others and you assign these values using the umask 007 by running this command in the initialization file or moving to the directory and opening the file you created and running this command.