Advance RegEx - Look-Ahead / Look-Behind My Cheatsheet

Ever want to match the "Qua" in "Quality" but not in "Quantity"?

What you need is to get familiar with Look-Ahead!

For quick reference, my cheatsheet as below.

[linux] How to backup DVD to ISO file

Simple backing up my DVDs for personal use, because:
- some disc are scratched and not played well on some DVD player
- convenient to stream them to a smart TV or a media player

one single command line:

dd if=/dev/sr0 of=./image.iso bs=4m && sync

linux (eg. ubuntu) format USB and check health status

 usb drive doesn't have health data. 

First, find the drive device using df  or  lsblk

Eg. unmount the device sdc1

$ umount /dev/sdc1

Format usb drive to FAT32 on linux

    $ sudo mkfs.vfat -F 32 /dev/sdc1

Check disk for bad blocks by writing different byte patterns

WARNING!  Write mode is destructive. 

    $ sudo badblocks -w -s -o  myusb.log /dev/sdc

        # write-mode,  show progress, output to file 

# non-destructive 

    $ sudo badblocks -nvs > usberr.log /dev/sdc

# or through   fsck  or  mkfs

    # option:   -fcky    or      -fccky    # one 'c' read-only,  'cc'  read-write non-destructive