## 1.52.22 filter

    set filter <filename wildcard> <filter command>

The `set filter` command allows input filter programs to be specified to allow Pyxplot to deal with file types that are not in the plaintext format which it ordinarily expects. Firstly the pattern used to recognise the filenames of the data files to which the filter should apply to must be specified; the standard wildcard characters `*` and `?` may be used. Then a filter program should be specified, along with any necessary command-line switches which should be passed to it. This program should take the name of the file to be filtered as the final option on its command line, immediately following any command-line switches specified above. It should output a suitable Pyxplot data fileon its standard output stream for Pyxplot to read. For example, to filter all files that end in `.foo` through the a program called `defoo` using the `–text` option one would type:

    set filter "*.foo" "/usr/local/bin/defoo --text"