How to apply chmod 777 command to gain permissions to be able read the content of auth.log which is located under the /var/log directory

Question

 student@Ubuntu:/$ ls -l
    total 80
    drwxr-xr-x   1 root root 4096 May  9  2021 bin
    drwxr-xr-x   2 root root 4096 Apr 24  2018 boot
    drwxr-xr-x   5 root root  360 Nov 23 19:50 dev
    drwxr-xr-x   1 root root 4096 Nov 23 19:50 etc
    drwxr-xr-x   1 root root 4096 May  9  2021 home
    drwxr-xr-x   1 root root 4096 May  9  2021 lib
    drwxr-xr-x   2 root root 4096 Apr 16  2021 lib64
    drwxr-xr-x   2 root root 4096 Apr 16  2021 media
    drwxr-xr-x   2 root root 4096 Apr 16  2021 mnt
    drwxr-xr-x   1 root root 4096 May  9  2021 opt
    dr-xr-xr-x 167 root root    0 Nov 23 19:50 proc
    drwx------   1 root root 4096 May  9  2021 root
    drwxr-xr-x   1 root root 4096 May  9  2021 run
    drwxr-xr-x   1 root root 4096 May  9  2021 sbin
    drwxr-xr-x   2 root root 4096 Apr 16  2021 srv
    dr-xr-xr-x  13 root root    0 Nov 23 19:50 sys
    drwxrwxrwt   1 root root 4096 Nov 23 19:52 tmp
    drwxr-xr-x   1 root root 4096 Apr 16  2021 usr
    drwxr-xr-x   1 root root 4096 Apr 16  2021 var
    student@Ubuntu:/$ cd tmp
    student@Ubuntu:/tmp$ cat /var/log/auth.log
    cat: /var/log/auth.log: Permission denied
    student@Ubuntu:/tmp$ cd ..
    student@Ubuntu:/$ cd sys
    student@Ubuntu:/sys$ cat /var/log/auth.log
    cat: /var/log/auth.log: Permission denied
    student@Ubuntu:/sys$ chmod 777 sys
    chmod: cannot access 'sys': No such file or directory
    student@Ubuntu:/sys$ cd ..
    student@Ubuntu:/$ chmod 777 sys
    chmod: changing permissions of 'sys': Read-only file system
    student@Ubuntu:/$ chmod 777 var
    chmod: changing permissions of 'var': Operation not permitted

Don't play around with permissions of system files.Use `sudo cat /var/log/auth.log` if you want to see the content of the logfile. — mook765, Nov 23 '21 at 21:23
student@Ubuntu:~$ cat /var/log/auth.log cat: /var/log/auth.log: Permission denied student@Ubuntu:~$ That is why I need change permissions to be able accomplish a task. — Michael260, Nov 23 '21 at 21:30
... or add your user to the `adm` group, which is provided for exactly this scenario — steeldriver, Nov 23 '21 at 21:31

score 3 · Accepted Answer · edited Nov 24 '21 at 00:13

If you want to see the content of /var/log/auth.log you just need to make use of the sudo-command:

sudo cat /var/log/auth.log

will prompt you for your password and then display the content of the file.

Don't change permissions of system files, you'd easily end up with a reinstall of your operating system.

Alternatively you could add the user to the adm-group with

sudo adduser $USER adm

Followed by logout/login, groups are applied at login time.

This will make the use of the sudo-command unnecessary.

How to apply chmod 777 command to gain permissions to be able read the content of auth.log which is located under the /var/log directory

1 Answers1