docs:tips_n_tricks:linux.html
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Table of Contents
Linux
Commands
Some Linux commands seldom used - so sometimes not remembered
which | find executables (candidates) |
---|---|
watch | repeat command and display output |
pv | Pipe Viewer |
System
Some tipp 'n tricks to handle you linux system in seldom situations
Rescan Blockdevices / Reread Partition Tables
Tipps I found with variable usefullness:
blockdev --rereadpt /dev/sda7
(from VMWare Communities)
partprobe /dev/sdX
hdparm -z /dev/sda
sfdisk -R /dev/sda
echo 1 > /sys/block/sdX/device/rescan
echo "scsi remove-single-device X X X X" > /proc/scsi/scsi echo "scsi add-single-device X X X X" > /proc/scsi/scsi
(X X X X
is <AdapterNo.> <Channel> <Id> <LUN>)
echo "- - -" > /sys/class/scsi_host/host<N>/scan
(see Linux Journal)
echo "scsi scsi-scan-devices" > /proc/scsi/scsi
partprobe [options]
(Thanks to linux-poweredge)
sfdisk -R
Force hard reset
In case you are in danger, that your remote system might hang while doing a clean shutdown, a “cold reboot” triggered by software might help
Please understand: The running system is affected the same way as when suddenly switching off the power supply with no battery attached!
This is no clean shutdown
echo b > /proc/sysrq-trigger
Credits and further reading: GEEX, ct' online, kernel.org git.kernel.org
Reset USB device (bus?)
Regain access to an build-in card reader after
udisksctl power-off -b /dev/sdc
/var/log/syslog
Feb 26 16:38:27 myhost udisksd[6074]: Ignoring SCSI command START STOP UNIT failure (Non-GOOD SCSI status from SGIO v3 ioctl: status=2 host_status=0 driver_status=8) on /dev/sdc Feb 26 16:38:27 myhost udisksd[6074]: Powered off /dev/sdc - successfully wrote to sysfs path /sys/devices/pci0000:00/0000:00:1d.7/usb2/2-4/remove Feb 26 16:38:27 myhost kernel: [179303.432273] usb 2-4: USB disconnect, device number 8 Feb 26 16:38:27 myhost colord: device removed: sysfs-HP-HP_Flash_Media_Reader Feb 26 16:38:28 myhost colord-sane: io/hpmud/pp.c 627: unable to read device-id ret=-1
succeeded with:
echo 0 > /sys/bus/usb/drivers/usb/usb2/authorized echo 1 > /sys/bus/usb/drivers/usb/usb2/authorized
Credits: How do you reset a USB Device from the command line? - Ask Ubuntu
Avoid accidental wakeups after hibernate with systemd
- /etc/systemd/sleep.conf.diff
diff -u -r1.1 sleep.conf --- sleep.conf 2020-04-01 19:23:42+02 1.1 +++ sleep.conf 2022-10-07 10:19:04+02 @@ -18,7 +18,7 @@ #AllowHybridSleep=yes #SuspendMode= #SuspendState=mem standby freeze -#HibernateMode=platform shutdown +HibernateMode=shutdown #HibernateState=disk #HybridSleepMode=suspend platform shutdown #HybridSleepState=disk
References:
docs/tips_n_tricks/linux.html.1672232665.txt.gz · Last modified: 28.12.2022 14:04 CET by peter