How to Save the Output of a Linux Command to a File

This short but detailed guide will show you how to save the output of a command that you’ve run in Linux as a file you can then view.

If you administer a Linux machine it is quite likely that you see a lot of messages fly by on your screen as you run commands. Some of these messages are trivial, while others may be critical. Although Linux and UNIX have a fine logging engine in syslogd and most of the system’s messages are logged in a proper log format in various files under he /var/log directory, you might find it useful sometimes to log the output of a command or script that you have run. Linux provides a number of ways to log the output of your commands.

The simplest, and probably the most common way to do this is to put a greater than sign after a command, followed by the location of the output file.

# ls /var/log > /tmp/varlog.log

The command shown above logs the output of the command ls /var/log into the file /tmp/varlog.log. One thing to note about this command is that if you use a single greater than sign to log the output the output of a command to a file it will create a new file if not already present, or wipe clean, if one is found. So, if you want to append the output of the command to a file you need to use two greater than signs instead of one. The command shown above needs to be modified to look like this:

# ls /var/log >> /tmp/varlog.log

Linux has a tool aptly named logsave which does a similar task as greater than sign. You can attain the same result as the first example using the following command:

# logsave /tmp/varlog.log ls /var/log

This command will create a new or overwrite an existing one with the output of the command ls /var/log. If you want logsave to append the out to a file instead of writing over it, using it with the -a option:

# logsave -a /tmp/varlog.log ls /var/log

There isn’t much of a difference between the greater than and the logsave method. The one thing I noticed was that logsave has a much cleaner output and it also adds the date to the output file.

If this article helped you, I'd be grateful if you could share it on your preferred social network - it helps me a lot. If you're feeling particularly generous, you could buy me a coffee and I'd be super grateful :)

buy a coffee for

Home » Linux » How to Save the Output of a Linux Command to a File

Leave a Comment

Your email address will not be published. Required fields are marked *