[Top] [Prev] [Next]

15.15 Listing Basic Information about Data Objects in an HDF File: hdfls

15.15.1 General Description

 The hdfls utility provides general information about the tags, reference numbers, and if requested, lengths of the data elements.

The hdfls utility provides general information about the HDF data objects in a file. This information includes the tags and reference numbers of the data objects, the lengths and offsets of the HDF object's data elements, the contents of DD blocks, and information regarding special elements. In situations where the DD block information is not needed, we recommend the hdp utility with the list command and its options.

15.15.2 Command-line Syntax

hdfls [-o][-l][-d][-v][-g][-s][-h][-t #] filename
 When no flags are used, hdfls displays data objects ordered by the tags and reference numbers. Contents of the DD blocks and lengths and offsets of the data elements are not displayed.

The option flags are described in Table 15K.

TABLE 15K
-o

 Order off:

 Turns off ordering. Displays data objects in the order in which they are listed in the DD block. Sequential data objects in the DD block with the same tag are grouped together.

-l

 Long format:

 Displays data objects in ascending tag and reference number order along with the length of each data element.

-d

 Offset/length:

 Displays two lists.

Displays tags and reference numbers of the data objects and offsets and lengths of the corresponding data elements in the order in which the objects appear in the DD blocks.

Then lists data objects in ascending tag and reference number order

-v

 Verbose:

 Displays annotation and label text, along with the information triggered by the -l flag

-g

 Group contents:

 Displays the contents of each group, along with the information triggered by the -l flag.

-s

 Special elements:

 Displays information about each special element, along with the information triggered by the -l flag

-h

 DD block:

 Displays DD block header information and DD block contents followed by the list of data objects in tag and reference number ascending order.

-t

 Tag:

 Lists information about the data objects with the specified tag. Must be followed by a tag number.

hdfls Option Flags

15.15.3 Examples

 The file SDSchunked.hdf, created by the example..... in Chapter 3, contains one chunked data set.

hdfls -s can be used to display information about the data objects and special elements in this file. Note that data objects are listed in tag and reference number ascending order.

For example, the command

hdfls -s SDSchunked.hdf
would display the following output:




SDSchunked.hdf:



File library version: Major= 4, Minor=1, Release=2



String=NCSA HDF post Version 4.1 Release 2, March 1998






Linked Blocks Indicator       : (tag 20)



        Ref no      1         12 bytes



        Ref no      2         34 bytes



        Ref no      3       4096 bytes






Version Descriptor            : (tag 30)



        Ref no      1         92 bytes






Data Chunk                    : (tag 61)



        Ref no      1         12 bytes



        Ref no      2         12 bytes



        Ref no      3         12 bytes



        Ref no      4         12 bytes



        Ref no      5         12 bytes



        Ref no      6         12 bytes






Number type                   : (tag 106)



        Ref no     12          4 bytes






SciData dimension record      : (tag 701)



        Ref no     12         22 bytes






Numeric Data Group            : (tag 720)



        Ref no      2         16 bytes






Vdata                         : (tag 1962)



        Ref no      4        116 bytes



        Ref no      7         60 bytes



        Ref no      9         60 bytes



        Ref no     11         60 bytes






Vdata Storage                 : (tag 1963)



        Ref no      7          4 bytes



        Ref no      9          4 bytes



        Ref no     11          2 bytes






Vgroup                        : (tag 1965)



        Ref no      8         33 bytes



        Ref no     10         33 bytes



        Ref no     13         60 bytes



        Ref no     14         47 bytes






Special Scientific Data       : (tag 17086)



        Ref no      3         72 bytes



        Chunked Element:



        logical size: 12



        number of dimensions: 2



        array of chunk lengths for each dimension:       3       2






Special Vdata Storage         : (tag 18347)



        Ref no      4         72 bytes



        Linked Block: first 12 standard 4096 per unit 16





 
[Top] [Prev] [Next]








hdfhelp@ncsa.uiuc.edu



HDF User's Guide - 05/19/99, NCSA HDF  
Development Group.