To find out does the remote host or server is up or down, you can use one small command called `ping` in Linux command line.
Imagine that you have a file in URL and you need to download it from the Linux command line. You can use a simple `wget` http client which can be found in many Linux distros.
You can easily download a URL from Linux command line by using ´wget´, and its default behavior is to save the file. However, you might want to disable the saving the file and just make the request.
If you have a file in URL and you want to download it from the Linux terminal, you can use the `wget` http client which is very easy to use.
For example, we have a webserver log file which contains access requests including IP addresses of the client. We want to list all unique IP addresses found in that file.
To list all the email addresses from the file, we use grep and regexp match email addresses from the file.
To find files newer than 1 day (or any number of days) you are most likely trying to find files that has last modification time, the mtime, newer than that specific date, meaning that the content has changed.
To find files that has been accessed but not changed during last 1 day (or any number of days) you are most likely trying to find files that has last access time, the atime, newer than that specific date.
In order to find files that are older than 1 day (or any number of days) you propably need files whose has last modification time, the mtime, is older than that specific date, meaning that the content has changed.
To find files that has been accessed but not changed before last 24 hours (or any number of hours) you need to find files whose last access time, the atime, is older than the specific date.