Linux / Unix: please help as much as you can. Thanks.

(1) What do the following commands do? Explain in detail.

a. cat # ie when you type carriage return after typing cat b. chmod -R 700 $HOME

(2) Identify command options and arguments in the following

$ ls -a -r /tmp /usr . $ fold -80 /etc/passwd > /tmp/passwd $ uname -S amazon $ cat -A /tmp

(3) List name(s) of commands available in Unix system for the following

a. to create a directory structure project.d/project.d/project.d from your home directory without using

multiple commands. b. to list the first 20 lines in a file

(4) Explain what we do in the following set of commands.

$ pwd /home/john $ echo $HOME /home/john $ ln -s $HOME /tmp/$HOME.$$ <--- Explain this $ cd /usr/src/cmd/usr/src/cmd $ pwd /usr/src/cmd/usr/src/cmd $ cd ../../cmd/bin/usr/src <--- Explain this

(5) Using chmod write cmds for the following.

a. change the file perms to read and write by user and no other perms for others. b. Add perms to a file to be readable by other and group.