Question

Create a new file and create a hard link and a symbolic link to it. Use vim or redirection to add content of the original file, then use cat and wc to examine each of the two aliases that you created. How does the result prove or disprove that either alias is a copy of the original file?

In your home directory create a hard link and a symbolic link to one of the commands that you know how to use in /usr/bin. For each verify whether or not you can use your hard or symbolic link to execute the command.

Create both a hard link and a symbolic link to the symbolic link you created in the previous step. If either of these work this introduces 2 levels of indirection which you can think of as: file2 -> file1 -> cmd

Record the commands you used. Test and report on which (if any) of these secondary links can be used as an alias to the command.

Answer 1

N. B.

According to your requirement I have executed the command sequentially and give you the recorded command list.

"iteradmin@C126-C072:~$" This is the user name i have used.

For creation of Hard link it may ask for sudo password. you can use sudo at the beginning of link command

For Soft link use -s in ln command (Ex- ln -s source_file_name link_file_name) and for hard link don't use -s (Ex- ln source_file_name link_file_name)

The Exact command for Execution are as follows (recorded)

iteradmin@C126-C072:~$ touch linktest.txt

iteradmin@C126-C072:~$ cat linktest.txt

iteradmin@C126-C072:~$ ln -s linktest.txt softlink

iteradmin@C126-C072:~$ ln linktest.txt hardlink

iteradmin@C126-C072:~$ cat > linktest.txt

link test for Sot link and Hard link

iteradmin@C126-C072:~$ cat linktest.txt

link test for Sot link and Hard link

iteradmin@C126-C072:~$ cat softlink

link test for Sot link and Hard link

iteradmin@C126-C072:~$ cat hardlink

link test for Sot link and Hard link

iteradmin@C126-C072:~$ wc linktest.txt

1 8 37 linktest.txt

iteradmin@C126-C072:~$ wc softlink

1 8 37 softlink

iteradmin@C126-C072:~$ wc hardlink

1 8 37 hardlink

iteradmin@C126-C072:~$ ls -l softlink

lrwxrwxrwx 1 iteradmin iteradmin 12 Feb 18 17:04 softlink -> linktest.txt

iteradmin@C126-C072:~$ ls -l hardlink

-rw-r--r-- 2 iteradmin iteradmin 37 Feb 18 17:05 hardlink

iteradmin@C126-C072:~$ ln -s /usr/bin/who softlink_cmd

iteradmin@C126-C072:~$ ln -s /usr/bin/who hardlink_cmd

iteradmin@C126-C072:~$ export PATH=$PATH:$PWD

iteradmin@C126-C072:~$ softlink_cmd

iteradmin :0 2020-02-18 15:11 (:0)

iteradmin@C126-C072:~$ hardlink_cmd

iteradmin :0 2020-02-18 15:11 (:0)

iteradmin@C126-C072:~$ who

iteradmin :0 2020-02-18 15:11 (:0)

iteradmin@C126-C072:~$ ln -s softlink_cmd softlink_cmd_l

iteradmin@C126-C072:~$ ln hardlink_cmd hardlink_cmd_l

iteradmin@C126-C072:~$ softlink_cmd_l

iteradmin :0 2020-02-18 15:11 (:0)

iteradmin@C126-C072:~$ hardlink_cmd_l

iteradmin :0 2020-02-18 15:11 (:0)

iteradmin@C126-C072:~$ ls -l softlink_cmd_l

lrwxrwxrwx 1 iteradmin iteradmin 12 Feb 18 17:12 softlink_cmd_l -> softlink_cmd

iteradmin@C126-C072:~$ ls -l softlink_cmd

lrwxrwxrwx 1 iteradmin iteradmin 12 Feb 18 17:09 softlink_cmd -> /usr/bin/who

iteradmin@C126-C072:~$ ls -l hardlink_cmd_l

lrwxrwxrwx 2 iteradmin iteradmin 12 Feb 18 17:09 hardlink_cmd_l -> /usr/bin/who

iteradmin@C126-C072:~$ ls -l hardlink_cmd

lrwxrwxrwx 2 iteradmin iteradmin 12 Feb 18 17:09 hardlink_cmd -> /usr/bin/who

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Explanation

It is proof that the alias is a copy of the original file because the contents written is copied to link file and tested using cat and wc commands. Also in ls -l command it showing the link of original and alias.

We can execute the link command (both Sot and Hard) by setting the path of home directory to PATH environment variable using export PATH command.

secondary links can be used as an alias to the command.

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