Article Directory
atrm
Delete the specified task in the pending task queue
Supplementary Note
atrmThe command is used to delete the specified task in the pending task queue.
grammar
atrm [选项] [参数]
options
-V: Display the version number.
parameter
- Task number: Specify the task to be deleted in the queue to be executed.
example
delete queued tasks
atq # 显示当前已经设置的任务
2 Mon May 17 08:00:00 2010 a root
1 Sat May 15 17:00:00 2010 a root
atrm 2 # 删除任务2
colrm
Delete the specified column in the file
Supplementary Note
colrmcommand is used to delete the specified column in the file. colrmA command reads input from standard input and outputs it to standard output. If no parameters are given, colrmthe command will not filter any lines.
grammar
colrm [参数]
parameter
- Starting column number: specify the starting column to be deleted;
- Ending Column Number: Specifies the ending column to delete.
hdparm
Display and set hard disk parameters
Supplementary Note
hdparmThe command provides a command line interface for reading and setting IDE or SCSI hard disk parameters.
grammar
hdparm [选项] [参数]
options
-a<缓存分区>: Set the number of partitions pre-stored in the buffer when reading files. If no<缓存分区>option is added, the current setting is displayed.-A<0或1>: Enable or disable caching when reading files.-c<I/O模式>: Set IDE 32-bit I/O mode.-C: Detect the power management mode of the IDE hard disk.-d<0或1>: Set the DMA mode of the disk.-f: Write the data in the memory buffer to the hard disk and clear the buffer.-g: Display parameters such as tracks, heads, and sectors of the hard disk.-h: Display help.-i: Display the hardware specification information of the hard disk, which is provided by the hard disk itself when booting.-I: Directly read the hardware specification information provided by the hard disk.-k<0或1>: When resetting the hard disk, keep-dmuthe parameter setting.-K<0或1>: When resetting the hard disk, keep-APSWXZthe parameter setting.-m<扇区数>: Set the number of partitions for multi-partition access on the hard disk.-n<0或1>: Ignore errors that occur during hard disk writing.-p<PIO模式>: Set the PIO mode of the hard disk.-P<分区数>: Set the number of partitions in the internal cache of the hard disk.-q: Do not display any information on the screen when executing subsequent parameters.-r<0或1>: Set the read/write mode of the hard disk.-S<时间>: Set the waiting time before the hard disk enters power saving mode.-t: Evaluate the read efficiency of the hard disk.-T: Evaluate the read efficiency of hard disk cache.-u<0或1>: When accessing the hard disk, other interrupt requests are allowed to be executed at the same time.-v: Display the relevant settings of the hard disk.-w<0或1>: Set the write cache of the hard disk.-X<传输模式>: Set the transfer mode of the hard disk.-y: Make the IDE hard disk enter the power saving mode.-Y: Put the IDE hard disk into sleep mode.-Z: Turn off the automatic power saving function of some Seagate hard drives.
parameter
- Device file: Specify the device file name corresponding to the id driver.
example
Display the relevant settings of the hard disk:
hdparm /dev/sda
/dev/sda:
IO_support = 0 (default 16-bit)
readonly = 0 (off)
readahead = 256 (on)
geometry = 19457［柱面数］/255［磁头数］/63［扇区数］, sectors = 312581808［总扇区数］, start = 0［起始扇区数］
Display the number of cylinders, heads, and sectors of the hard disk:
hdparm -g /dev/sda
/dev/sda:
geometry = 19457［柱面数］/255［磁头数］/63［扇区数］, sectors = 312581808［总扇区数］, start = 0［起始扇区数］
Test the read speed of the hard disk:
hdparm -T /dev/sda
/dev/sda:
Timing cached reads: 4684 MB in 2.00 seconds = 2342.92 MB/sec
Test the read speed of hard disk cache:
hdparm -T /dev/xvda
/dev/xvda:
Timing cached reads: 11154 MB in 1.98 seconds = 5633.44 MB/sec
Detect the power management mode of the hard disk:
hdparm -C /dev/sda
/dev/sda:
drive state is: standby [省电模式]
Query and set the number of sectors accessed by multiple sectors of the hard disk to improve the access efficiency of the hard disk:
hdparm -m /dev/sda
hdparm -m # 参数值为整数值如8 /dev/sda
Attachment: Hard Disk Bad Sector Repair Method
Check: smartctl -l selftest /dev/sda
Uninstall: umount /dev/sda*
Fix:badblocks /dev/sda
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