dd: redocument after removing info from clap help

src/uu/dd/dd.md

@@ -0,0 +1,122 @@
+<!-- spell-checker:ignore convs iseek oseek -->
+# dd
+
+## About
+Copy, and optionally convert, a file system resource
+
+## After Help
+
+OPERANDS:
+
+    bs=BYTES        read and write up to BYTES bytes at a time (default: 512);
+                    overwrites ibs and obs.
+    cbs=BYTES       the 'conversion block size' in bytes. Applies to
+                    the conv=block, and conv=unblock operations.
+    conv=CONVS      a comma-separated list of conversion options or
+                    (for legacy reasons) file flags.
+    count=N         stop reading input after N ibs-sized read operations rather
+                    than proceeding until EOF. See iflag=count_bytes if stopping 
+                    after N bytes is preferred
+    ibs=N           the size of buffer used for reads (default: 512)
+    if=FILE         the file used for input. When not specified, stdin is used instead
+    iflag=FLAGS     a comma-separated list of input flags which specify how the input
+                    source is treated. FLAGS may be any of the input-flags or 
+                    general-flags specified below.
+    skip=N          (or iseek=N) skip N ibs-sized records into input before beginning 
+                    copy/convert operations. See iflag=seek_bytes if seeking N bytes 
+                    is preferred.
+    obs=N           the size of buffer used for writes (default: 512)
+    of=FILE         the file used for output. When not specified, stdout is used 
+                    instead
+    oflag=FLAGS     comma separated list of output flags which specify how the output 
+                    source is treated. FLAGS may be any of the output flags or 
+                    general flags specified below
+    seek=N          (or oseek=N) seeks N obs-sized records into output before 
+                    beginning copy/convert operations. See oflag=seek_bytes if 
+                    seeking N bytes is preferred
+    status=LEVEL    controls whether volume and performance stats are written to 
+                    stderr.
+                             
+                    When unspecified, dd will print stats upon completion. An example is below.
+                        6+0 records in
+                        16+0 records out
+                        8192 bytes (8.2 kB, 8.0 KiB) copied, 0.00057009 s, 14.4 MB/s
+                    The first two lines are the 'volume' stats and the final line is 
+                    the 'performance' stats.
+                    The volume stats indicate the number of complete and partial 
+                    ibs-sized reads, or obs-sized writes that took place during the 
+                    copy. The format of the volume stats is
+                    <complete>+<partial>. If records have been truncated (see 
+                    conv=block), the volume stats will contain the number of 
+                    truncated records.
+                    
+                    Possible LEVEL values are:
+                        progress: Print periodic performance stats as the copy 
+                            proceeds.
+                        noxfer: Print final volume stats, but not performance stats.
+                        none: Do not print any stats.
+
+                    Printing performance stats is also triggered by the INFO signal 
+                    (where supported), or the USR1 signal. Setting the 
+                    POSIXLY_CORRECT environment variable to any value (including an
+                    empty value) will cause the USR1 signal to be ignored.
+
+CONVERSION OPTIONS:
+
+    ascii       convert from EBCDIC to ASCII. This is the inverse of the 'ebcdic'
+                option. Implies conv=unblock.
+    ebcdic      convert from ASCII to EBCDIC. This is the inverse of the 'ascii'
+                option. Implies conv=block.
+    ibm         convert from ASCII to EBCDIC, applying the conventions for '[', ']' 
+                and '~' specified in POSIX. Implies conv=block.
+
+    ucase       convert from lower-case to upper-case
+    lcase       converts from upper-case to lower-case.
+
+    block       for each newline less than the size indicated by cbs=BYTES, remove 
+                the newline and pad with spaces up to cbs. Lines longer than cbs are 
+                truncated.
+    unblock     for each block of input of the size indicated by cbs=BYTES, remove
+                right-trailing spaces and replace with a newline character.
+
+    sparse      attempts to seek the output when an obs-sized block consists of only
+                zeros.
+    swab        swaps each adjacent pair of bytes. If an odd number of bytes is
+                present, the final byte is omitted.
+    sync        pad each ibs-sided block with zeros. If 'block' or 'unblock' is
+                specified, pad with spaces instead.
+    excl        the output file must be created. Fail if the output file is already
+                present.
+    nocreat     the output file will not be created. Fail if the output file in not
+                already present.
+    notrunc     the output file will not be truncated. If this option is not
+                present, output will be truncated when opened.
+    noerror     all read errors will be ignored. If this option is not present, dd
+                will only ignore Error::Interrupted.
+    fdatasync   data will be written before finishing.
+    fsync       data and metadata will be written before finishing.
+
+INPUT FLAGS:
+
+    count_bytes     a value to count=N will be interpreted as bytes.
+    skip_bytes      a value to skip=N will be interpreted as bytes.
+    fullblock       wait for ibs bytes from each read. zero-length reads are still
+                    considered EOF.
+
+OUTPUT FLAGS:
+
+    append      open file in append mode. Consider setting conv=notrunc as well.
+    seek_bytes  a value to seek=N will be interpreted as bytes.
+
+GENERAL FLAGS:
+
+    direct      use direct I/O for data.
+    directory   fail unless the given input (if used as an iflag) or output (if used 
+                as an oflag) is a directory.
+    dsync       use synchronized I/O for data.
+    sync        use synchronized I/O for data and metadata.
+    nonblock    use non-blocking I/O.
+    noatime     do not update access time.
+    nocache     request that OS drop cache.
+    noctty      do not assign a controlling tty.
+    nofollow    do not follow system links.

src/uu/dd/src/dd.rs

@@ -732,6 +732,7 @@ pub fn uu_app<'a>() -> Command<'a> {
     Command::new(uucore::util_name())
         .version(crate_version!())
         .about(ABOUT)
+        .after_help(AFTER_HELP)
         .infer_long_args(true)
         .arg(Arg::new(options::OPERANDS).multiple_values(true))
 }