Working with Files in CentOS

Note: After the lab starts up, please wait a minute or so to give the instance time to spin up before connecting via SSH.

Once you ssh in, become root with:

sudo -i

We need to look at the CPUs on the system. That information is stored in /proc/cpuinfo.

If we cat that file, we notice we only have one CPU so we can just use head -5 to get the relevant information.

To do this, run:

head -5 /proc/cpuinfo > /tmp/cpus

If we had more than one CPU, we could use grep -A 4 processor /proc/cpuinfo to get information about all of them. The -A flag tells grep to print four lines after it matches, and we're looking for "processor", which is the first line of the /proc/cpuinfo file.

1. Get the format for today's date:

   tail /var/log/messages
   

2. Copy and paste the date.

3. Run the following, and output it to the terminal to make sure it looks right:

   grep "<DATE> " /var/log/messages
   

4. Once we verify it looks right, run:

   grep "<DATE> " /var/log/messages > /tmp/logs
   

Since /etc/passwd contains all the users on the system, we just need to count how many lines are in that file. Fortunately, the wc command will do that for us.

Run:

wc -l /etc/passwd > /tmp/usernum