NAME¶
fitsdiff - compare two FITS image files and report the differences in header
keywords and data.
SYNOPSIS¶
fitsdiff [
OPTION]...
FILE1 FILE2
DESCRIPTION¶
fitsdiff is a command line script based on pyfits to compare two FITS
image files and report the differences in header keywords and data.
FILE1 and
FILE2 are the two files to be compared. They may also be
wild cards, in such cases, they must be enclosed by double or single quotes,
or they may be directory names. If both are directory names, all files in each
of the directories will be included; if only one is directory name, then the
directory name will be prefixed to the file name(s) specified by the other
argument. For example:
- % fitsdiff "*.fits" "/machine/data1"
will compare all FITS files in the current directory to the corresponding files
in the directory
/machine/data1.
If the two files are identical within the specified conditions, it will report
"No difference is found." If the value(s) of
-c and
-k
takes the form
@filename, list is in the text file
filename, and
each line in that text file contains one keyword.
fitsdiff commandline arguments can also be set using the environment
variable
FITSDIFF_SETTINGS. If the
FITSDIFF_SETTINGS environment
variable is present, each argument present will override the corresponding
argument on the commandline. This environment variable exists to make it
easier to change the behavior of
fitsdiff on a global level, such as in
a set of regression tests.
GENERIC OPTIONS¶
- -h, --help
- Display terse usage information (help).
- -q, --quiet
- Produce no output and just return a status code.
- -n INTEGER, --num-diffs=INTEGER
- Max number of data differences (image pixel or table element) to report
per extension (default 10).
- -d NUMBER, --difference-tolerance=NUMBER
- The relative tolerance for comparison of two numbers, specifically two
floating point numbers. This applies to data in both images and tables,
and to floating point keyword values in headers (default 0.0).
- -b, --no-ignore-blanks
- Don't ignore trailing blanks (whitespace) in string values. Otherwise
trailing blanks both in header keywords/values and in table column values)
are not treated as significant i.e. without this option 'ABC ' and 'ABC'
are considered equivalent.
- --no-ignore-blank-cards
- Don't ignore entirely blank cards in headers. Normally fitsdiff
does not consider blank cards when comparing headers, but this will ensure
that even blank cards match up.
- -o FILE, --output-file=FILE
- Output results to this file; otherwise results are printed to stdout.
- -k KEYWORDS, --ignore-keywords=KEYWORDS
- Comma-separated list of keywords not to be compared. Keywords may contain
wildcard patterns. To exclude all keywords, use "*"; make sure
to have double or single quotes around the asterisk.
- -c KEYWORDS, --ignore-comments=KEYWORDS
- Comma-separated list of keywords whose comments will not be compared.
Wildcards may be used as with --ignore-keywords.
TABLE COMPARISON OPTIONS¶
- -f COLUMNS, --ignore-fields=COLUMNS
- Comma-separated list of fields (i.e. columns) not to be compared. All
columns may be excluded using "*" as with
--ignore-keywords.
EXAMPLES¶
% fitsdiff -k filename,filtnam1 -n 5 -d 1.e-6 test1.fits test2
This command will compare files
test1.fits and
test2.fits, report
maximum of 5 different pixels values per extension, only report data values
larger than 1.e-6 relative to each other, and will neglect the different
values of keywords
FILENAME and
FILTNAM1 (or their very
existence).