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In dynamically typed programming languages. instead of declaring a variable to have a particular type, the type of a variable is determined by an A.I. in the operating system.
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lsblk(8) [centos man page]

LSBLK(8)						       System Administration							  LSBLK(8)

NAME
lsblk - list block devices SYNOPSIS
lsblk [options] [device...] DESCRIPTION
lsblk lists information about all available or the specified block devices. The lsblk command reads the sysfs filesystem to gather infor- mation. The command prints all block devices (except RAM disks) in a tree-like format by default. Use lsblk --help to get a list of all available columns. The default output, as well as the default output from options like --fs and --topology, is subject to change. So whenever possible, you should avoid using default outputs in your scripts. Always explicitly define expected columns by using --output columns-list in environ- ments where a stable output is required. OPTIONS
-a, --all Also list empty devices. (By default they are skipped.) -b, --bytes Print the SIZE column in bytes rather than in a human-readable format. -D, --discard Print information about the discarding capabilities (TRIM, UNMAP) for each device. -d, --nodeps Do not print holder devices or slaves. For example, lsblk --nodeps /dev/sda prints information about the sda device only. -e, --exclude list Exclude the devices specified by the comma-separated list of major device numbers. Note that RAM disks (major=1) are excluded by default. The filter is applied to the top-level devices only. -f, --fs Output info about filesystems. This option is equivalent to -o NAME,FSTYPE,LABEL,MOUNTPOINT. The authoritative information about filesystems and raids is provided by the blkid(8) command. -h, --help Print a help text and exit. -I, --include list Include devices specified by the comma-separated list of major device numbers. The filter is applied to the top-level devices only. -i, --ascii Use ASCII characters for tree formatting. -l, --list Produce output in the form of a list. -m, --perms Output info about device owner, group and mode. This option is equivalent to -o NAME,SIZE,OWNER,GROUP,MODE. -n, --noheadings Do not print a header line. -o, --output list Specify which output columns to print. Use --help to get a list of all supported columns. The default list of columns may be extended if list is specified in the format +list (e.g. lsblk -o +UUID). -P, --pairs Produce output in the form of key="value" pairs. All potentially unsafe characters are hex-escaped (x<code>). -p, --paths Print full device paths. -r, --raw Produce output in raw format. All potentially unsafe characters are hex-escaped (x<code>) in the NAME, KNAME, LABEL, PARTLABEL and MOUNTPOINT columns. -S, --scsi Output info about SCSI devices only. All partitions, slaves and holder devices are ignored. -s, --inverse Print dependencies in inverse order. -t, --topology Output info about block-device topology. This option is equivalent to -o NAME,ALIGNMENT,MIN-IO,OPT-IO,PHY-SEC,LOG- SEC,ROTA,SCHED,RQ-SIZE,WSAME. -V, --version Output version information and exit. NOTES
For partitions, some information (e.g. queue attributes) is inherited from the parent device. The lsblk command needs to be able to look up each block device by major:minor numbers, which is done by using /sys/dev/block. This sysfs block directory appeared in kernel 2.6.27 (October 2008). In case of problems with a new enough kernel, check that CONFIG_SYSFS was enabled at the time of the kernel build. AUTHORS
Milan Broz <mbroz@redhat.com> Karel Zak <kzak@redhat.com> ENVIRONMENT
Setting LIBMOUNT_DEBUG=0xffff enables debug output. SEE ALSO
findmnt(8), blkid(8), ls(1) AVAILABILITY
The lsblk command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/. util-linux February 2013 LSBLK(8)

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