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This article mainly explains "the usage of the Linux basic command eject". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "the usage of the Linux basic command eject".

Eject

The eject instruction allows removable media (usually optical discs, floppy disks, tapes, or Jaz or ZIP disks) to be ejected under software control. This command can also control some multi-CD converters with automatic eject functions supported by some devices, and close the disks of some CD drives.

The corresponding device is ejected. The name can be a device file or mount point, a complete path, or "/ dev", "/ media", or "/ mnt" omitted previously. If no name is specified, the default name "cdrom" is used.

There are four different eject methods depending on whether the device is a CD ROM, SCSI device, removable floppy disk, or tape. By default, pop-up tries all four methods sequentially until it succeeds. If the device is currently installed, uninstall it before ejecting.

The scope of this command: RedHat, RHEL, Ubuntu, CentOS, SUSE, openSUSE, Fedora.

1. Grammar

Eject-h

Eject [- vnrsfmqp] []

Eject [- vn]-d

Eject [- vn]-an on | off | 1 | 0 []

Eject [- vn]-c slot []

Eject [- vn]-I on | off | 1 | 0 []

Eject [- vn]-t []

Eject [- vn]-T []

Eject [- vn]-x []

Eject [- vn]-X []

Eject-V

2. List of options

Option

Description

-h |-- help

Display simple help documentation

-V |-- version

Display command version information, and then exit

-v |-- verbose

The details are displayed when the instruction is executed, and you can see what the instruction is doing on the command line

-d |-- default

Displays the default device name (cdrom)

-an on | 1 | off | 0

This option controls the automatic pop-up mode and is supported only by some devices. If this switch is enabled, the device will pop up automatically when it is turned off.

-c |-- changerslot

Using this option, you can select a CD slot from the ATAPI/IDE CD-ROM converter. Linux2.0 or later is required to use this feature. When a change request is working, the CD-ROM drive (mounted data CD or music CD) cannot be used. Also notice that the first slot of the converter is called 0, not 1.

-I on | 1 | off | 0

This option locks the flyout so that it does not work. When enabled, the drive will not eject when the button is pressed. This is useful when you carry a laptop in a bag or box and do not want it to pop up if the button is inadvertently pressed.

-t |-- trayclose

With this option, the drive is given a CD-ROM tray close command. Not all devices support this command.

-T |-- traytoggle

If the CD-ROM tray is open, it will be closed; if the CD-ROM tray is closed, it will eject. Not all devices support this command because it uses the CD-ROM tray close command above.

-x |-- cdspeed

With this option, the CDROM drive can select the speed. The speed parameter is a number that indicates the desired speed (for example, 8 for 8X speed), or 0 for the most big data speed. Not all devices support this command, and you can only specify the speed that the drive can achieve. This option is cleared each time the media changes. This option can be used alone or with the-t and-c options.

-X |-- listspeed

Displays the available speed of the cdrom. Using this option, the CD-ROM drive is probed to detect the available speed. Outputs a list of speeds that can be used as an argument to the-x option. This applies only to Linux2.6.13 or later, and only the maximum speed is reported on previous versions. Also note that some drives may not report speed correctly, so the options do not apply to them.

-n |-- noop

Displays the selected device, but does nothing

-r |-- cdrom

Eject cdrom Devic

-s |-- scsi

Eject SCSI Devic

-f |-- floppy

Eject floppy Devic

-Q |-- tape

Eject tape device

-p |-- proc

Allow / proc/mounts instead of / etc/mtab

-m |-- no-umount

This option allows eject to work with device drivers that automatically mount removable media, so these devices must always be mounted. This option tells eject not to attempt to uninstall a given device, even if it is mounted based on / etc/mtab or / proc/ mount.

3 、 example

Function

Instruction

Pop up default Devic

Eject

Pop up a device or mount point named cdrom

Eject cdrom

Use the device name to pop up

Eject / dev/cdrom

Use the mount point to eject

Eject / mnt/cdrom

Eject the 4th IDE device

Eject hdd

Eject the first SCSI device

Eject sda

Pop up using the SCSI partition name

Eject sda4

Select disk 5 on a multi-disk switch

Eject-v-c4 / dev/cdrom

Turn on the automatic eject function on the sound projector CD-ROM

Eject-an on / dev/sbpcd

4. Description

The eject instruction returns 0 after successful execution and 1 if it fails.

The eject directive applies only to devices that support one or more of the four pop-up methods. This includes most CD-ROMs (IDE, SCSI, and proprietary), some SCSI tape drives, Jaz drives, ZIP drives (parallel ports, SCSI and IDE versions), and LS 120 removable floppy disks. Users also reported that floppy drives were also successful on Sun SPARC and Apple Macintosh systems. If the eject does not work, it is likely to be a limitation on the kernel driver of the device, rather than the popup itself.

The-r,-s,-f, and-Q options allow you to control the method used for pop-up. You can specify multiple methods. If these options are not specified, all four options are tried (which is good in most cases).

Eject is not always able to determine whether a device is installed (for example, whether it has multiple names). If the device name is a symbolic link, the pop-up will follow the link and use the device it points to.

If eject determines that the device can have multiple partitions, it will attempt to uninstall all installed partitions for the device before popping up. If the uninstall fails, the program will not attempt to eject the media.

You can pop up an audio CD. If the drive is empty, some CDROM will refuse to open the tray. Some devices do not support the pallet close command.

If the automatic eject feature is enabled, the drive will always eject after running this command. Not all linux kernel CDROM drivers support automatic pop-up mode and cannot find the state of automatic pop-up mode.

You need appropriate permissions to access device files. To eject some devices, such as SCSI devices, you need to run as root or setuidroot.

The heuristic method (given name) for finding the device is shown below. If the name ends with a trailing slash, delete it (to support the filename generated using the shell filename). If the name is "." Or "/", try to open it as a device file or mount point. If it fails, it attempts to put'/ dev/','/ media/','/ mnt/','/ dev/cdroms','/ dev/rdsk/','/ dev/dsk/', and last'. /'in front of the name until it finds a device file or mount point that can be opened. Install the device's program check / etc/mtab. If it fails, it also checks / etc/fSTAB to find the mount point of the currently unmounted device.

It is recommended that you create symbolic links, such as / dev/cdrom or / dev/zip, so that eject can use an easy-to-remember name to determine the appropriate device.

To save the type, you can create a shell alias for the pop-up options for specific settings work.

5. Examples

1) No device type is specified, and cdrom is popped up directly. In this case, all methods are tried in turn until they pop up.

[root@localhost ~] # eject-v / / use-v to display the process of instruction execution

Eject: using default device `cdrom'

Eject: device name is `cdrom'

Eject: expanded name is `/ dev/cdrom'

Eject: `/ dev/cdrom' is a link to` / dev/sr0'

Eject: `/ dev/sr0' is not mounted

Eject: `/ dev/sr0' is not a mount point

Eject: checking if device "/ dev/sr0" has a removable or hotpluggable flag

Eject: `/ dev/sr0' is not a multipartition device

Eject: trying to eject `/ dev/sr0' using CD-ROM eject command / / try the first pop-up method

Eject: CD-ROM eject command failed

Eject: trying to eject `/ dev/sr0' using SCSI commands / / try the second pop-up method

Eject: SCSI eject succeeded

2) use the "- r" option to pop up cdrom

[root@localhost ~] # mount / / check whether there is a CD mount

/ dev/mapper/VolGroup-lv_root on / type ext4 (rw)

...

/ dev/sr0 on / media/VBox_GAs_5.2.16 type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)

[root@localhost] # eject-v-r / / eject CD

Eject: using default device `cdrom'

...

Eject: trying to eject `/ dev/sr0' using CD-ROM eject command

Eject: CD-ROM eject command succeeded

Thank you for your reading, the above is the content of "the usage of the Linux basic command eject". After the study of this article, I believe you have a deeper understanding of the usage of the Linux basic command eject, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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