14.3 Editing the file header

The keywords in a XAS file header are normally set by the program which generates the file, and may be altered (added or modified) by other programs which manipulate the file, or inherited by children files. In particular a sequence of HISTORY keywords keep track of the manipulations done.

It is however possible to edit one header keyword at a time also manually using the appropriate program. This command can be invoked in two ways :

```
header_edit [ file keyword value(s)
```
is the form used to edit an existing keyword. If the keyword is an array of numeric values, one can supply as many values as the original array contains. If the keyword is a character string, one can supply a string as long as the original value. In no case a keyword can be extended beyond the creation length, or changed of type.
```
header_edit [ file keyword value keytype
```
is the form used to add a new keyword. New keywords are always scalar quantities. One must supply also the appropriate keyword data type.

Note that "duplicatable" keywords (typically HISTORY and COMMENT) are always interpreted as new keywords. It is not possible to alter the previous values of an existing duplicatable keyword. It is also not possible to assign as a value a string containing imbedded blanks.

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sax.iasf-milano.inaf.it/Xashelp/handle.3.html :: original creation 2002 Sep 04 18:11:03 CEST :: last edit 2002 Sep 04 18:11:03 CEST