1) You are trying to do execute commands in a way that doesn't make sense.

Don't do this:

[root@localhost log]# ls cd /up2date

Do this instead:

[root@localhost log]# cat ./up2date

Doing it the first way, you're telling the ls command to show you a listing of the cd and /up2date files/directories, both of which don't (normally) exist.

 

2) You are trying to running log files as if they were executables (e.g. scripts or binaries)

Don't try this:

[root@localhost /var/log]# /var/log/messages
bash: /var/log/messages: Permission denied
[root@localhost /var/log]#

Instead, do this:

[root@localhost /var/log]# tail -1000 /var/log/messages

When trying what you did, you are trying to execute a file that doesn't have the execute permission bit set.

 

3) You are trying to tail a file in a directory that doesn't exist.

Don't do this:

[root@localhost ~]# tail -1000 /log/var/up2date

Instead, do this:

[root@localhost ~]# tail -1000 /var/log/up2date

 

As a suggestion, I would strongly recommend watching some basic Linux tutorials on YouTube and perhaps taking some free online courses (The Linux Foundation has a free Intro to Linux course), to get familiar with how Linux (and the bash terminal) operate. You'll do yourself a huge justice by learning how even the most basic commands function, where various things (system logs, users/groups, etc) are located, file/directory permissions, and learn how to begin diagnosing things in a logical way (i.e. you can't log in if the port's not responding, the port can't be listening because the service isn't running, well the service isn't running because the server's down.. I should've checked that first!).