[SOLVED] bash function to check if script dependencies are installed...

masavini · 02-18-2016, 04:08 AM

hi,
all of my bash scripts start with something like this:

Code:

dependencies=('jq' 'wget')
checkScriptDependencies "${dependencies[@]}"

here is the code for checkScriptDependencies:

Code:

checkScriptDependencies () { # "${dependencies[@]}"
	local _packages=( "$@" )
	local _package=
	for _package in ${_packages[@]}; do
		hash $_package
		if (( $? > 0 )); then
			sudo apt-get -y install $_package
		fi
	done
}

it works pretty good, but it will fail if the command name doesn't match the package name.
hxnormalize and hxselect, for example, are installed with html-xml-utils package.

if html-xml-utils is not installed, then, hash hxnormalize will fail but sudo apt-get install hxnormalize will fail as well...

could you suggest how to deal with such a case?

thanks!

pan64 · 02-18-2016, 05:46 AM

I do not really understand what do you need, but apt-get install --print-uris <package> will print all the missing/required packages

masavini · 02-18-2016, 06:14 AM

well, it's pretty simple...

the aim is to check if a command can be executed. if not, install the required package.

if the command is hxnormalize, sudo apt-get install hxnormalize will not find hxnormalize package as it does not exist: hxnormalize is part of html-xml-utils package.

using hxnormalize as input, how can i install html-xml-utils package?

pan64 · 02-18-2016, 06:15 AM

that is: apt-cache search hxnormalize

a4z · 02-18-2016, 06:17 AM

why don't check if 'wanted_binary' exists, with whichor test, and only search for it if it's not found,

however,
http://manpages.ubuntu.com/manpages/...g-query.1.html

can also be callled via dpkg

http://manpages.ubuntu.com/manpages/...n1/dpkg.1.html
-S --search option

Quote:

-S, --search filename-search-pattern...
Search for a filename from installed packages.

so it seems this is what you want

Quote:

dpkg -S hxnormalize

masavini · 10-23-2017, 07:30 PM

Quote:

apt-cache search hxnormalize

Quote:

dpkg -S hxnormalize

those commands only work if html-xml-utils package is already installed.

in my case, however, html-xml-utils is not installed yet (otherwise hxnormalize command would already be executable!).

i know this thread is pretty old, but i'm resurrecting it just because i finally found a (quite ugly, but working) solution:

Code:

$cat script.bash:
#!/usr/bin/env bash

# this script needs 'hxnormalize' and 'mvn' commands.


# this function checks if its arguments can be executed.
# if they're not, it installs the repository package providing each missing command.
# if a missing command has multiple candidate packages (i.e. mvn, or mysql), ask which should be installed.

function install_if_needed () {

    local needed_packages=()
    local package_name
    local command_name
    for command_name in "$@"; do

      # if this command is already executable, do nothing and continue with the next
      hash "${command_name}" 2>/dev/null \
        && continue

      # if the command is not installed, execute command-not-found builtin and save the stderr to a file
      /usr/lib/command-not-found -- "${command_name}" &> error.txt \
        || true


      # if error.txt contains the string '${command_name}: command not found', it means that
      # the command does not exist in any repository package and can not be installed
      grep -q "${command_name}: command not found" error.txt \
        && echo "command '${command_name}' does not exist in any package. exiting..." > /dev/tty \
        && return 1


      # otherwise error.txt contains the package name:
      # $ cat error.txt
      # The program 'transmission-edit' is currently not installed. You can install it by typing:
      # sudo apt-get install transmission-cli
      package_name=$(awk '/^sudo apt-get/{print $NF}' error.txt)


      # if var $package_name is empty, it means several candidate packages are found:
      # $ cat error.txt
      # The program 'mysql' can be found in the following packages:
      #  * mysql-client-core-5.5
      #  * mariadb-client-core-5.5
      #  * mysql-client-core-5.6
      #  * percona-xtradb-cluster-client-5.5
      # Try: sudo apt-get install <selected package>
      if [[ -z "${package_name}" ]]; then

        local candidate_packages=$(awk '/^ \* /{print $NF}' error.txt)

        echo -e "\nselect a package to install for '${command_name}' command:" > /dev/tty
        select package_name in ${candidate_packages}; do
          break
        done

      fi

      needed_packages+=("${package_name}")

    done


    # if no package is needed, just return
    [[ "${needed_packages[0]:-}" ]] || return 0


    # otherwise update and install
    sudo apt-get -qq update \
      && sudo apt-get --quiet --assume-yes install "${needed_packages[@]}"

    return 0
}


dependencies=('hxnormalize' 'mvn')
install_if_needed "${dependencies[@]}"

exit 0

what do you think about?

David the H. · 11-05-2017, 05:43 AM

The apt-file program can be used to learn which packages contain a given program/filename.

It would probably not be the cleanest option though. apt-file would need to be installed first and its database kept up-to-date, then the output would need to be parsed to get the name(s) you need.

A package search also came up with auto-apt. It's not clear from the description whether it can be used to supply script dependencies:

Quote:

auto-apt checks the file access of programs running within its environments, and if a program tries to access a file known to belong in an uninstalled package, auto-apt will install that package using apt-get. This feature requires apt and sudo to work.

It also provides simple database to search which package contains a requested file.

Other than that, I say it's probably just better to list out the dependencies the script needs and let the user figure the rest out.