10
votes
3answers
355 views

Read the middle of a large file

I have a 1 TB file. I would like to read from byte 12345678901 to byte 19876543212 and put that on standard output on a machine with 100 MB RAM. I can easily write a perl script that does this. ...
2
votes
1answer
37 views

Equivalent of memmove on files: copy a range of bytes to an earlier position

What is an equivalent of memmove on files with the same input and output file? dd works when I move the file contents towards the right, but not if I move the contents left, since there's no handling ...
3
votes
2answers
497 views

How to write file into another

I have an empty file (only zeroes are in it) of size 9,0KB and I need to write another file (with size 1,1KB) to it, but the first file must not lose its size or the rest of its contents. So if the ...
16
votes
3answers
1k views

How can you trim files using the command line?

What is the console equivalent of the following Python code: target = file("disk", "w") # create a file target.seek(2*1024*1024*1024) # skip to 2 GB target.write("\0") target.close() Maybe some ...
5
votes
2answers
2k views

Unpack files and directories from an image created by dd?

I created an image of an NTFS partition using dd. I wonder if I can unload/unpack the files and directories in the image to any partition whose size is larger than the image size, so that I can ...
5
votes
1answer
1k views

Are there alternatives for `dd`?

What other tools should I use to read and write files with truncation, seeking and skipping. dd's command line options seem inconvenient and foreign and I don't like choosing between slow, but precise ...
1
vote
2answers
2k views

How to write a file at various offsets to a filesystem partition with dd command

Requirement I want to write a file at various offsets into the partition Partition /dev/part2 is mounted at /mypart I tried the command below: dd if=/dev/urandom of=/mypart/aaa bs=1024 seek=0 ...