Write all 1s to file using dd

It is easy to create a file consisting of all zeros in Linux using dd and the /dev/zero device.

$ dd if=/dev/zero count=100 bs=1 > outfile


So how do you create a file consisting of all binary ones? There is no device to create binary ones so you have to do something like the following:

$ dd if=/dev/zero count=100 bs=1 | tr "\000" "\377" > outfile


You can use xxd to see the contents of the resultant file:

$ xxd -b outfile
0000000: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000006: 11111111 11111111 11111111 11111111 11111111 11111111  ......
000000c: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000012: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000018: 11111111 11111111 11111111 11111111 11111111 11111111  ......
000001e: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000024: 11111111 11111111 11111111 11111111 11111111 11111111  ......
000002a: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000030: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000036: 11111111 11111111 11111111 11111111 11111111 11111111  ......
000003c: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000042: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000048: 11111111 11111111 11111111 11111111 11111111 11111111  ......
000004e: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000054: 11111111 11111111 11111111 11111111 11111111 11111111  ......
000005a: 11111111 11111111 11111111 11111111 11111111 11111111  ......
0000060: 11111111 11111111 11111111 11111111                    ....
$ 

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