RGBCube/uutils-coreutils
1
Fork 0
mirror of https://github.com/RGBCube/uutils-coreutils synced 2025-07-28 11:37:44 +00:00
Code Issues Activity

dd: truncate to specified seek length

Browse source 
When specifying `seek=N` and *not* specifying `conv=notrunc`, truncate
the output file to `N` blocks instead of truncating it to zero before
starting to write output. For example

    $ printf "abc" > outfile
    $ printf "123" | dd bs=1 skip=1 seek=1 count=1 status=noxfer of=outfile
    1+0 records in
    1+0 records out
    $ cat outfile
    a2

Fixes #3068.
This commit is contained in:
Jeffrey Finkelstein 2022-02-05 13:58:05 -05:00
parent ebf33d775e
commit 1af709f642
2 changed files with 28 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

22
tests/by-util/test_dd.rs
View file

@ -604,5 +604,27 @@ fn test_seek_bytes() {
.stdout_is("\0\0\0\0\0\0\0\0abcdefghijklm\n");
}
#[test]
fn test_seek_do_not_overwrite() {
let (at, mut ucmd) = at_and_ucmd!();
let mut outfile = at.make_file("outfile");
outfile.write_all(b"abc").unwrap();
// Skip the first byte of the input, seek past the first byte of
// the output, and write only one byte to the output.
ucmd.args(&[
"bs=1",
"skip=1",
"seek=1",
"count=1",
"status=noxfer",
"of=outfile",
])
.pipe_in("123")
.succeeds()
.stderr_is("1+0 records in\n1+0 records out\n")
.no_stdout();
assert_eq!(at.read("outfile"), "a2");
}
// conv=[ascii,ebcdic,ibm], conv=[ucase,lcase], conv=[block,unblock], conv=sync
// TODO: Move conv tests from unit test module