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--- linux_wiki:dd [2015/03/09 22:54]
billdozor
+++ linux_wiki:dd [2019/05/25 23:50]
@@ Line 1: / Line 1: @@
-====== dd ======
-**General Information**
-Using dd to create a USB bootable image.
-**Checklist**
-  * Distros: All
-----
-===== The command =====
-<code bash>
-dd if=~/image.iso of=/dev/sdx oflag=direct  bs=2MB
-</code>
-==== Explanation ====
-  * if = in file, the location of source image
-  * of = output file, the location of the USB device. x is the drive letter.
-  * oflag direct = bypass the cache and write direct to disk
-  * bs = write in the specified block size
-----
-===== Get DD status =====
-To get a progress report while dd is running, you need to open another virtual terminal, and then send a special USR1 signal to the dd process.
-First, find out the process id of the dd process by running the following in the new virtual terminal.
-<code bash>
-pgrep -l '^dd$'
-dd
-</code>
-To send the USR1 signal to the dd prcoess:
-<code bash>
-kill -USR1  8789
-</code>
-As soon as the USR1 signal is detected, dd will print out the current statistics to its STDERR.
-<code bash>
-$ dd if=/dev/random of=/dev/null bs=1K count=100
-+14 records in
-+14 records out
-bytes (204 B) copied, 24.92 seconds, 0.0 kB/s
-</code>
-Use the watch command to execute kill at a set interval. (every 10 seconds in this case)
-<code bash>
-watch -n 10 kill -USR1 8789
-</code>
-----
-===== Alternative DD status =====
-Another method of getting dd status is using pv.
-PV "monitors the progress of data through a pipe".
-The dd command then becomes:
-<code bash>
-dd if=~/image.iso | pv -petr | of=/dev/sdx oflag=direct  bs=2MB
-</code>
-pv options
-  * -p : show progress bar
-  * -e : estimated time remaining
-  * -t : timer on, show total time running
-  * -r : rate of data transfer