1CONFMODULE(3) Library Functions Manual CONFMODULE(3)
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6 confmodule - communicate with Debian configuration system FrontEnd.
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9 #!/bin/sh -e
10 . /usr/share/debconf/confmodule
11 db_version 2.0
12 db_capb 'backup'
13 CAPB=$RET
14 db_input 'foo/bar' || true
15 db_go || true
16
18 This is a library of shell functions that eases communication with
19 Debian's configuration management system. It can communicate with a
20 FrontEnd via the debconf protocol. The design is that each command in
21 the protocol is represented by one function in this module. The func‐
22 tionname is the same as the command, except it is prefixed with "db_"
23 and is lower-case. Call the function and pass in any parameters you
24 want to follow the command. Any textual return code from the FrontEnd
25 will be returned to you in the $RET variable, while the numeric return
26 code from the FrontEnd will be returned as a return code (and so those
27 return codes must be captured or ignored).
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30 Once this library is loaded, any text you later output will go to stan‐
31 dard error, rather than standard output. This is a good thing in gen‐
32 eral, because text sent to standard output is interpreted by the Fron‐
33 tEnd as commands. If you do want to send a command directly to the
34 FrontEnd, you must output it to file descriptor 3, like this:
35 echo GET foo/bar >&3
36 The library checks to make sure it is actually speaking to a FrontEnd
38 by examining the DEBIAN_HAS_FRONTEND variable. If it is set, a FrontEnd
39 is assumed to be running. If not, the library turns into one, and runs
40 a copy of the script that loaded the library connected to it. This
41 means that if you source this library, you should do so very near to
42 the top of your script, because everything before the sourcing of the
43 library may well be run again.
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46 debconf-devel(7), dpkg-preconfigure(8), dpkg-reconfigure(8), deb‐
47 conf_specification in the debian-policy package
48
50 Joey Hess <joeyh@debian.org>
51 CONFMODULE(3)