I'm working on a Ubuntu system and currently this is what I'm doing:
if ! which command > /dev/null; then
echo -e "Command not found! Install? (y/n) \c"
read
if "$REPLY" = "y"; then
sudo apt-get install command
fi
fi
Is this what most people would do? Or is there a more elegant solution?
dpkg-query --showformat='${db:Status-Status}'
This produces a small output string which is unlikely to change and is easy to compare deterministically without grep:
pkg=hello
status="$(dpkg-query -W --showformat='${db:Status-Status}' "$pkg" 2>&1)"
if [ ! $? = 0 ] || [ ! "$status" = installed ]; then
sudo apt install $pkg
fi
The $? = 0 check is needed because if you've never installed a package before, and after you remove certain packages such as hello, dpkg-query exits with status 1 and outputs to stderr:
dpkg-query: no packages found matching hello
instead of outputting not-installed. The 2>&1 captures that error message too when it comes preventing it from going to the terminal.
For multiple packages:
pkgs='hello certbot'
install=false
for pkg in $pkgs; do
status="$(dpkg-query -W --showformat='${db:Status-Status}' "$pkg" 2>&1)"
if [ ! $? = 0 ] || [ ! "$status" = installed ]; then
install=true
break
fi
done
if "$install"; then
sudo apt install $pkgs
fi
The possible statuses are documented in man dpkg-query as:
n = Not-installed
c = Config-files
H = Half-installed
U = Unpacked
F = Half-configured
W = Triggers-awaiting
t = Triggers-pending
i = Installed
The single letter versions are obtainable with db:Status-Abbrev, but they come together with the action and error status, so you get 3 characters and would need to cut it.
So I think it is reliable enough to rely on the uncapitalized statuses (Config-files vs config-files) not changing instead.
dpkg -s exit status
This unfortunately doesn't do what most users want:
pkgs='qemu-user pandoc'
if ! dpkg -s $pkgs >/dev/null 2>&1; then
sudo apt-get install $pkgs
fi
because for some packages, e.g. certbot, doing:
sudo apt install certbot
sudo apt remove certbot
leaves certbot in state config-files, which means that config files were left in the machine. And in that state, dpkg -s still returns 0, because the package metadata is still kept around so that those config files can be handled more nicely.
To actually make dpkg -s return 1 as desired, --purge would be needed:
sudo apt remove --purge certbot
which actually moves it into not-installed/dpkg-query: no packages found matching.
Note that only certain packages leave config files behind. A simpler package like hello goes directly from installed to not-installed without --purge.
Tested on Ubuntu 20.10.
Python apt package
There is a pre-installed Python 3 package called apt in Ubuntu 18.04 which exposes an Python apt interface!
A script that checks if a package is installed and installs it if not can be seen at: How to install a package using the python-apt API
Here is a copy for reference:
#!/usr/bin/env python
# aptinstall.py
import apt
import sys
pkg_name = "libjs-yui-doc"
cache = apt.cache.Cache()
cache.update()
cache.open()
pkg = cache[pkg_name]
if pkg.is_installed:
print "{pkg_name} already installed".format(pkg_name=pkg_name)
else:
pkg.mark_install()
try:
cache.commit()
except Exception, arg:
print >> sys.stderr, "Sorry, package installation failed [{err}]".format(err=str(arg))
Check if an executable is in PATH instead
See: How can I check if a program exists from a Bash script?
See also
I've settled on one based on Nultyi's answer:
MISSING=$(dpkg --get-selections $PACKAGES 2>&1 | grep -v 'install$' | awk '{ print $6 }')
# Optional check here to skip bothering with apt-get if $MISSING is empty
sudo apt-get install $MISSING
Basically, the error message from dpkg --get-selections is far easier to parse than most of the others, because it doesn't include statuses like "deinstall". It also can check multiple packages simultaneously, something you can't do with just error codes.
Explanation/example:
$ dpkg --get-selections python3-venv python3-dev screen build-essential jq
dpkg: no packages found matching python3-venv
dpkg: no packages found matching python3-dev
screen install
build-essential install
dpkg: no packages found matching jq
So grep removes installed packages from the list, and awk pulls the package names out from the error message, resulting in MISSING='python3-venv python3-dev jq', which can be trivially inserted into an install command.
I'm not blindly issuing an apt-get install $PACKAGES, because as mentioned in the comments, this can unexpectedly upgrade packages you weren't planning on; not really a good idea for automated processes that are expected to be stable.
It seems that nowadays apt-get has an option --no-upgrade that just does what the OP wants:
--no-upgradeDo not upgrade packages. When used in conjunction with install, no-upgrade will prevent packages listed from being upgraded if they are already installed.
Manpage from https://linux.die.net/man/8/apt-get
Therefore you can use
apt-get install --no-upgrade package
and package will be installed only if it's not.
Inspired by Chris' answer:
#! /bin/bash
installed() {
return $(dpkg-query -W -f '${Status}\n' "${1}" 2>&1|awk '/ok installed/{print 0;exit}{print 1}')
}
pkgs=(libgl1-mesa-dev xorg-dev vulkan-tools libvulkan-dev vulkan-validationlayers-dev spirv-tools)
missing_pkgs=""
for pkg in ${pkgs[@]}; do
if ! $(installed $pkg) ; then
missing_pkgs+=" $pkg"
fi
done
if [ ! -z "$missing_pkgs" ]; then
cmd="sudo apt install -y $missing_pkgs"
echo $cmd
fi
This explicitly prints 0 if installed else 1 using only awk:
dpkg-query -W -f '${Status}\n' 'PKG' 2>&1|awk '/ok installed/{print 0;exit}{print 1}'
or if you prefer the other way around where 1 means installed and 0 otherwise:
dpkg-query -W -f '${Status}\n' 'PKG' 2>&1|awk '/ok installed/{print 1;exit}{print 0}'
** replace PKG with your package name
Convenience function:
installed() {
return $(dpkg-query -W -f '${Status}\n' "${1}" 2>&1|awk '/ok installed/{print 0;exit}{print 1}')
}
# usage:
installed gcc && echo Yes || echo No
#or
if installed gcc; then
echo yes
else
echo no
fi
I had a similar requirement when running test locally instead of in Docker. Basically I only wanted to install any .deb files found if they weren't already installed.
# If there are .deb files in the folder, then install them
if [ `ls -1 *.deb 2> /dev/null | wc -l` -gt 0 ]; then
for file in *.deb; do
# Only install if not already installed (non-zero exit code)
dpkg -I ${file} | grep Package: | sed -r 's/ Package:\s+(.*)/\1/g' | xargs dpkg -s
if [ $? != 0 ]; then
dpkg -i ${file}
fi;
done;
else
err "No .deb files found in '$PWD'"
fi
I guess the only problem I can see is that it doesn't check the version number of the package so if .deb file is a newer version. Then this wouldn't overwrite the currently installed package.
Kinda based off yours just a little more 'elegant'. Just because I'm bored.
#!/bin/bash
FOUND=("\033[38;5;10m")
NOTFOUND=("\033[38;5;9m")
PKG="${@:1}"
command ${PKG} &>/dev/null
if [[ $? != 0 ]]; then
echo -e "${NOTFOUND}[!] ${PKG} not found [!]"
echo -e "${NOTFOUND}[!] Would you like to install ${PKG} now ? [!]"
read -p "[Y/N] >$ " ANSWER
if [[ ${ANSWER} == [yY] || ${ANSWER} == [yY][eE][sS] ]]; then
if grep -q "bian" /etc/os-release; then
sudo apt-get install ${PKG}
elif grep -q "arch" /etc/os-release; then
if [[ -f /bin/yay ]] || [[ -f /bin/yaourt ]]; then
yaourt -S ${PKG} 2>./err || yay -S ${PKG} 2>./err
else
sudo pacman -S ${PKG}
fi
elif grep -q "fedora" /etc/os-release; then
sudo dnf install ${PKG}
else
echo -e "${NOTFOUND}[!] This script couldn't detect your package manager [!]"
echo -e "${NOTFOUND}[!] Manually install it [!]"
fi
elif [[ ${ANSWER} == [nN] || ${ANSWER} == [nN][oO] ]]; then
echo -e "${NOTFOUND}[!] Exiting [!]"
fi
else
echo -e "${FOUND}[+] ${PKG} found [+]"
fi
The answers that suggest to use something along the lines of:
dpkg-query --showformat '${db:Status-Status}\n' --show $package | grep -q '^installed$'
dpkg-query --showformat '${Status}\n' --show $package | grep -q '^install ok installed$'
are correct.
But if you have the package dpkg-dev installed and you do not just want to check whether a package is installed but you also:
then you can abuse the dpkg-checkbuilddeps tool for this job:
dpkg-checkbuilddeps -d apt /dev/null
This will check whether apt is installed.
The following will check whether apt is installed in at least version 2.3.15 and grep is installed as amd64 and the virtual package x-window-manager is provided by some of the installed packages:
dpkg-checkbuilddeps -d 'apt (>= 2.3.15), grep:amd64, x-window-manager' /dev/null
The exit status of dpkg-checkbuilddeps will tell the script whether the dependencies are satisfied or not. Since this method supports passing multiple packages, you only have to run dpkg-checkbuilddeps once even if you want to check whether more than one package is installed.
Since you mentioned Ubuntu, and you want to do this programmatically(although dpkg variations can also be used but would be more complex to implement), this(which) will definitely work:
#!/bin/bash
pkgname=mutt
which $pkgname > /dev/null;isPackage=$?
if [ $isPackage != 0 ];then
echo "$pkgname not installed"
sleep 1
read -r -p "${1:-$pkgname will be installed. Are you sure? [y/N]} " response
case "$response" in
[yY][eE][sS]|[yY])
sudo apt-get install $pkgname
;;
*)
false
;;
esac
else
echo "$pkgname is installed"
sleep 1
fi
Although for POSIX compatibility, you would want to use command -v instead as mentioned in another similar question.
In that case,
which $pkgname > /dev/null should be replaced by command -v $pkgname in the above code sample.
I use the following way:
which mySQL 2>&1|tee 1> /dev/null
if [[ "$?" == 0 ]]; then
echo -e "\e[42m MySQL already installed. Moving on...\e[0m"
else
sudo apt-get install -y mysql-server
if [[ "$?" == 0 ]]; then
echo -e "\e[42mMy SQL installed\e[0m"
else
echo -e "\e[42Installation failed\e[0m"
fi
fi
I use this solution as I find it most straightforward.
function must_install(){
return "$(apt -qq list $var --installed 2> /dev/null |wc -l)"
}
function install_if() {
unset install
for var in "$@"
do
if $(must_install $var)
then
install+="${var} "
fi
done
if [ -n "$install" ];
then
sudo apt-get install -qy $install
fi
}
The neat thing is, must_install returns 1 or 0 which is then interpreted as true or false from the calling if, so we don't need any test using [].
install_if takes any number of packages separated by space.
The problem is apt is not meant to be used in scripts, so this might stop working at any time. 8)
All the answers are good but seem to be complex for beginners like myself to understand. so here is the solution that worked for me. My Linux environment is centOS but can't confirm it works for all distributions
PACKAGE_NAME=${PACKAGE_NAME:-node}
if ! command -v $PACKAGE_NAME > /dev/null; then
echo "Installing $PACKAGE_NAME ..."
else
echo "$PACKAGE_NAME already installed"
fi