In bash shell, using bind command you can view and modify the readline keybindings.

You can also set a value to a readline variable, or macro, or function.

You can either put this in the .inputrc, you can add it using the bind command rom the command line.

In the command line, by default it uses the emacs keybinding, but you can change it to vi keybindings.
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check_ping command is a Nagios plugin that is used to check the ping output of a remote server.

Based on the ping output, you can decide to set certain warning and critical threshold level, based on which Nagios can send notifications to you.

If you’ve installed Nagios from source, you’ll find all the default plugins under /usr/local/nagios/libexec directory.
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After you’ve installed RabbitMQ server, if you don’t pay attention, depending on the usage, the log files will get filled-up very quickly.

On my server, within a month, my RabbitMQ server log file reached around 5GB in size.

Log files will be located under $RABBIT_HOME/var/log/rabbitmq directory.

The name of the log file will be “rabbit\@dev-db.log”. dev-db is the name of my server where the RabbitMQ server is running.
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Compress is one of the compression utilities available on Linux.

This command does the compression and reduces the file size using the Lempel-Ziv algorithm.

The compressed file extension that is created by this utility is .Z
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check_ftp plugin is used to verify the status of your remote FTP server.

If you’ve installed Nagios from source, check_ftp command will be located in the /usr/local/nagios/libexec directory.
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From your java application, under certain circumstances, you might be getting “java.io.FileNotFoundException: Too many open files” error message.

There are two typical solutions to it:

  1. Check your application logic and make sure it is not opening too many files unnecessarily (for example, In a loop there is file open, but it is not getting closed anywhere)
  2. Increase the open files limit on your system.

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If you have not updated PCI IDs on your system in while, it is a good idea to keep it updated once in a while.

If you notice that lspci command is not displaying the proper device name for any of the devices that are connected to your PCI bus, this might be because the PCI IDs on your system is not current.

To update the PCI IDs, use update-pciids command.
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Using blkid command you can view attributes of block devices that are on your system.

This is a quick way to find the type of the block devices on your system.

This uses the libblkid library to get the values.
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Snapper is a Linux utility to take backups on Linux.

It is especially helpful to create multiple snapshots of your filesystem. Once you take a snapshot, you can later use that snapshot to restore files.
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Edquota command is used to edit the quotas for a user or group. This is just an editor, from where you can change the quota values.

By default, this will open up the quota file in an Vi editor, from where you can change the values. When you save the file, it will overwrite the original quota values for the user or group based on the one you’ve just entered.
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