dtfits dumps the contents of a FITS table in an ASCII format, either into a user-specified file or on stdout. The output is formatted on a fixed number of columns to make it readable by human beings. Additional informations are printed out before the table values are dumped, these informations can be skipped by using the -d option.
Last, if you want to dump the table into an easily parsable format (for a piece of software), you might want to use the -s option which specifies a character to use as separator. All data fields will be printed out separated by this character only. This allows to use string parsers to cut down the output lines into tokens by looking for this separator. Fields (lines) will still be delimited by the end-of-line character. This option produces ASCII tables which are easy to parse for a piece of software but mostly unreadable to human beings.
Notice that dtfits only accepts one single FITS table in input.
- Skip information output about the table and column names. Outputs only the table values. Beware that if the FITS file contains several extensions, they will all appear one after another, separated only by two blank lines. In that case, it would be preferrable to keep the complete output and parse out the returned stream to differentiate which data come from where.
- -s <char>
Use the character <char> as separator in output. This option is useful
if you want to produce a table that should be parsed by a piece of
software (see above description). The separator can only be a single
non-null character. To avoid special characters being interpreted by
the shell, it is recommended to provide this character always between
simple or double quotes. Example:
dtfits -s '&' table.tfits
If you want to use a special character as separator, such as a tab,
use ^V to insert your character, such as:
dtfits -s '^V<TAB>' table.tfits
which means: you type CTRL-V and then the tab key.
FITS tables are stored into extensions. If there are several tables in a file, they will all be displayed one after another in the same output stream.