NAME

hdiff -- Display the differences between two image headers.

USAGE

hdiff input1 input2

DESCRIPTION

The hdiff task prints the differences between two image headers on STDOUT. A line is printed each time a keyword is present in one image but not in the other, or when the value of the keyword is different between the two headers. If no differences are found, this task produces no output. Keyword comments, blank lines, and HISTORY and COMMENT keywords are always ignored. All groups will be checked unless a group specifier is added to the image name. The hidden parameter keywords controls which keywords will be checked for differences. If it is left blank, all keywords will be compared.

PARAMETERS

input[image template]

An image template containing the names of images to compare with those named in the second image template.

input[image template]

An image template containing the names of images to compare with those named in the first image template. The number of images in the first and second templates must match and the number of groups in each two images compared with each other must match.

(keywords = " ") [string]

A comma- or blank-delimited list of keywords to compare. Keyword names are not case sensitive. If the list is blank, all keywords will be compared. If the first character in the list is a "@", the rest of the string is treated as a file and the keywords are read from that file. If the first character in the list is a "~", keywords not in the list will be compared.

EXAMPLES

1. Compare the keywords fchnl, nchnls, nxsteps, and overscan in the images y1000.d0h and y1001.d0h:

to> hdiff y1000.d0h y1001.d0h key="fchnl,nchnls,nxsteps,overscan"

2. Compare all the images in a directory with their data quality masks for differences:

to> hdiff *.d0h *.%d0h%q0h%

BUGS

SEE ALSO

hselect, hcheck