Linux shell command to read/print file chunk by ch

问题:

Is there a standard Linux command i can use to read a file chunk by chunk? For example, i have a file whose size is 6kB. I want to read/print the first 1kB, and then the 2nd 1kB ... Seems cat/head/tail wont work in this case.

Thanks very much.

回答1:

dd will do it

dd if=your_file of=output_tmp_file bs=1024 count=1 skip=0

And then skip=1 for the second chunk, and so on.

You then just need to read the output_tmp_file to get the chunk.

回答2:

You could do this with read -n in a loop:

while read -r -d '' -n 1024 BYTES; do
    echo "$BYTES"
    echo "---"
done < file.dat

回答3:

split can split a file into pieces by given byte count

回答4:

Are you trying to actually read a text file? Like with your eyes? Try less or more

回答5:

you can use fmt

eg 10bytes

$ cat file
a quick brown fox jumps over the lazy dog
good lord , oh my gosh

$ tr '\n' ' '<file | fmt -w10 file
a quick
brown fox
jumps
over
the lazy
dog good
lord , oh
my gosh

each line is 10 characters. If you want to read the 2nd chunk, pass it to tools like awk ..eg

$ tr '\n' ' '<file |  fmt -w10 | awk 'NR==2' # print 2nd chunk
brown fox

To save each chunk to file, (or you can use split with -b )

$ tr '\n' ' '<file |  fmt -w10 | awk '{print $0 > "file_"NR}'