dumping pre/post install/remove/upgrade scripts as sh instead of bash

[sinhlam]

apologies if this has been asked/brought up before but I'm running into an odd issue.

I'm building deb packages with the before/after install/remove options and those are fine. I examine the postinst and preinst scripts in /var/lib/dpkg/info/package.* and what I've found is that when I specify a before/after upgrade option it executes those scripts as sh instead of bash.

something like this (from the preinst script):

#!/bin/sh


before_upgrade() {
    :
#!/bin/bash

echo "running pre-upgrade.sh"

exit 0

}

before_install() {
    :
#!/bin/bash
echo "running pre-inst.sh"

if I build a package without the upgrade options, those preinst/postinst scripts are executed as bash. normally the packages I make have explicit instructions to purge instead of "upgrading" them. only ran into this because I wanted to try going the upgrade route instead of the purge/install method.

thanks.

[jordansissel]

I'm open to this. I'm not exactly sure how best to implement it, though I have one idea -- fpm could check the first line for the hash-bang syntax #!/some/path and use that path as the first line of the template.

So in your example, the before_upgrade method has #!/bin/bash so the top line would then need to be #!/bin/bash and fpm should automatically do this. Thoughts?

[jordansissel]

Related issue -- looks like the same idea (having fpm use the correct shell) -- #1904

[sinhlam]

that sounds bout right. thinking further, if there is a method to detect that a #!/whatever/interpreter is present at the top, it should just run it as is, if it's missing well then assume it's a sh script. all of my scripts are all bash so either will work, just floating the idea that someone out there might be crazy enough to use ruby/go/python there instead of bash.