3.1.18. Log: Making and using command files

3.1.18.1. Overview

In many circumstances a user of SPEX wants to repeat his analysis for a different set of parameters. For example, after having analysed the spectrum of source A, a similar spectral model and analysis could be tried on source B. In order to facilitate such analysis, SPEX offers the opportunity to save the commands that were used in a session to an ascii-file. This ascii-file in turn can then be read by SPEX to execute the same list of commands again, or the file may be edited by hand.

The command files can be nested. Thus, at any line of the command file the user can invoke the execution of another command file, which is executed completely before execution with the current command file is resumed. Using nested command files may help to keep complex analyses manageable, and allow the user easy modification of the commands.

In order to facilitate the readability of the command files, the user can put comment lines in the command files. Comment lines are recognized by the first character, that must be #. Also blank lines are allowed in the command file, in order to enhance (human) readability.

3.1.18.2. Saving commands to file

After the command log save #a is given on the SPEX command line (#a is the file name), all the following commands entered by the user (NOT the ones before) are stored on the command file until the log close out command is given. Exceptions are the commands read from a nested command file (it is not necessary to save these commands, since they are already in the nested command file). Also, help calls and the command to open the file (“log save #a”) are not stored.

All commands are expanded to the full keywords before they are saved in the file. However, for execution this is not important, since the interpreter can read both abbrevated and full keywords.

Saving the commands to the command file can be stopped by giving the command log close save. The file with the saved commands is closed and remains at the specified path. SPEX will automatically append the extension “.com” to the filename.

3.1.18.3. Saving output to file

It is also possible to store all the output that is printed on the screen to a file. This is usefull for long sessions or for computer systems with a limited screen buffer. The output saved this way could be inspected later by (other programs of) the user. It is also useful if SPEX is run in a kind of batch-mode. The command to save the output is log out #a, where #a should be the filename without extension. SPEX will automatically append the extension “.out” to the filename.

3.1.18.4. Executing commands from file

ASCII files with the .com extension containing SPEX commands can be executed in SPEX using the command log execute #a, where #a stands for the file name without the “.com” extension. When a command file is read and the end of file is reached, the text “Normal end of command file encountered” is printed on the screen, and execution of the calling command file is resumed, or if the command file was opened from the terminal, control is passed over to the terminal again.

For example, the user may have a command file named run which does his entire analysis. This command file might start with the line log exe mydata that will run the command file mydata that contains all information regarding to the data sets read, further data selection or binning etc. This could be followed by a second line in run like “log exe mymodel” that runs the command file mymodel which could contain the set-up for the spectral model and/or parameters. Also, often used plot settings (e.g. stacking of different plot types) could easily placed in separate command files.

3.1.18.5. Syntax

The following syntax rules apply for command files:

log exe #a : Execute the commands from the file #a. The suffix “.com” will be automatically appended to this filename.

log save #a [overwrite] [append] : Store all subsequent commands on the file #a. The suffix “.com” will be automatically appended to this filename. The optional argument “overwrite” will allow to overwrite an already existing file with the same name. The argument “append” indicates that if the file already exists, the new commands will be appended at the end of this file.

log close save : Close the current command file where commands are stored. No further commands will be written to this file.

log out #a [overwrite] [append] : Store all subsequent screen output on the file #a. The suffix “.out” will be automatically appended to this filename. The optional argument “overwrite” will allow to overwrite an already existing file with the same name. The argument “append” indicates that if the file already exists, the new output will be appended at the end of this file.

log close output : Close the current ascii file where screen output is stored. No further output will be written to this file.

3.1.18.6. Examples

log save myrun : writes all subsequent commands to a new file named “myrun.com”. However, in case the file already exists, nothing is written but the user gets a warning instead.

log save myrun append : as above, but appends it to an existing file

log save myrun overwrite : as above, but now overwrites without warning any already existing file with the same name.

log close save : close the file where commands are stored.

log exe myrun : executes the commands in file myrun.com.

log output myrun : writes all subsequent output to file myrun.out.

log close output : closes the file above.