Bash:如何向存储在变量中的数组添加元素？

Question

TL；博士

在bash中有两个数组变量，archPkgs和npmPkgs。在后面的代码中，我有一个变量pkgPlatform，它可以指向这两个变量中的任何一个。我想通过这个变量向数组中添加一个元素。我怎么才能在巴什做到这一点？

详细信息

我正试图用Python和Bash编写一个安装后脚本，我正在编写一个bast脚本来安装所有所需的包。下面是它的代码。

# List of all Arch packages
archPkgs=(
        # Display server
        'xorg'

        # Display manager
        'lightdm'
        'lightdm-webkit2-greeter'
        'lightdm-webkit-theme-litarvan'

        # Editor
        'neovim-nightly-bin'

        # WM
        'i3-gaps'
        'i3lock'
        'i3status'
        'picom'
        'rofi'

        # Syncing
        'syncthing'

        # Printing
        'cups'

        # Networking
        'network-manager-applet'
        'avahi'
        'nss-mdns'
        'reflector'

        # Browsing
        'firefox'
        'firefox-nightly'

        # Terminals, shell, programming, and other programsn and utilities
        'kitty'
        'bash-completion'
        'nodejs'
        'npm'
        'python'
        'python-pip'

        # Notifications
        'dunst'

        # Gaming
        'steam'

        # Media
        'vlc'
        'playerctl'
        'spotify'

        # Audio
        'pasystray'
        'pulseaudio'
        'pulseaudio-alsa'
        'pulseaudio-bluetooth'
        'pavucontrol'
        'lib32-libpulse'
        'lib32-alsa-plugins'
        'alsa-utils'
        'alsa-firmware'

        # Fonts
        'noto-fonts-cjk'
        'noto-fonts-emoji'
        'ttf-iosevka'
        'ttf-liberation'
        'ttf-opensans'

        # Drive tools + backups
        'udiskie'
        'borg'

        # Power management
        'xfce4-power-manager'

        # Themes
        'arc-gtk-theme'
        'breeze'

        # Screenshots
        'flameshot'

        # Bluetooth
        'blueman'
        'bluez'
        'bluez-utils'
)

npmPkgs=(
    # Language servers
    'vim-language-server'
    'bash-language-server'

    # Type checkers
    'pyright'
)


while true; do
    echo Are there any packages you would like to manage? Enter [arch/npm] [add/remove][ name of package].
    read pkgPlatform pkgAction pkgName

    if [ "$pkgPlatform" == 'arch' ]; then
        pkgPlatform=archPkgs
    elif [ "$pkgPlatform" == 'npm' ]; then
        pkgPlatform=npmPkgs

    elif [ "$pkgPlatform" == 'quit' ] || [ "$pkgAction" == 'quit' ] || [ "$pkgAction" == 'quit' ]; then
        echo Continuing...
        break

    else
        echo "Unknown option."
        continue
    fi

    if [ "$pkgPlatform" != 'quit' ] && [ "$pkgAction" != 'quit' ] && [ "$pkgName" != 'quit' ]; then
        while true; do
            if [ "$pkgAction" == 'add' ]; then
                $pkgPlatform+=pkgName
                break

            elif [ "$pkgAction" == 'remove' ]; then
                unset "$pkgName"[$pkgPlatform]
                break

每当我运行它，就会发生这样的事情。

[johnny@lj-laptop post_install_scripts]$ ./02_pkgs.sh 
Packages to be installed:

Arch Packages
xorg lightdm lightdm-webkit2-greeter lightdm-webkit-theme-litarvan neovim-nightly-bin i3-gaps i3lock i3status picom rofi syncthing cups network-manager-applet avahi nss-mdns reflector firefox firefox-nightly kitty bash-completion nodejs npm python python-pip dunst steam vlc playerctl spotify pasystray pulseaudio pulseaudio-alsa pulseaudio-bluetooth pavucontrol lib32-libpulse lib32-alsa-plugins alsa-utils alsa-firmware noto-fonts-cjk noto-fonts-emoji ttf-iosevka ttf-liberation ttf-opensans udiskie borg xfce4-power-manager arc-gtk-theme breeze flameshot blueman bluez bluez-utils

npm Packages
vim-language-server bash-language-server pyright
Are there any packages you would like to manage? Enter [arch/npm] [add/remove] [name of package].
When you are satisfied, enter "quit" instead of "add" or "remove".
npm add test
./02_pkgs.sh: line 153: npmPkgs+=pkgName: command not found
Packages to be installed:

Arch Packages
xorg lightdm lightdm-webkit2-greeter lightdm-webkit-theme-litarvan neovim-nightly-bin i3-gaps i3lock i3status picom rofi syncthing cups network-manager-applet avahi nss-mdns reflector firefox firefox-nightly kitty bash-completion nodejs npm python python-pip dunst steam vlc playerctl spotify pasystray pulseaudio pulseaudio-alsa pulseaudio-bluetooth pavucontrol lib32-libpulse lib32-alsa-plugins alsa-utils alsa-firmware noto-fonts-cjk noto-fonts-emoji ttf-iosevka ttf-liberation ttf-opensans udiskie borg xfce4-power-manager arc-gtk-theme breeze flameshot blueman bluez bluez-utils

npm Packages
vim-language-server bash-language-server pyright
Are there any packages you would like to manage? Enter [arch/npm] [add/remove] [name of package].
When you are satisfied, enter "quit" instead of "add" or "remove".

问题似乎在第153行。

我现在不太确定我的选择是什么。我粘贴了所有系统更改行注释的脚本，但是在运行它之前，您仍然应该看看它。

很明显，这个脚本还没有完成，我计划早些时候重新安排很多东西。

Answer 1

变化

    if [ "$pkgPlatform" == 'arch' ]; then
        pkgPlatform=archPkgs
    elif [ "$pkgPlatform" == 'npm' ]; then
        pkgPlatform=npmPkgs

至

    if [ "$pkgPlatform" == 'arch' ] || [ "$pkgPlatform" == 'npm' ]; then
        declare -n platformPkgs="${pkgPlatform}Pkgs"

这使platformPkgs成为指向所需数组的nameref。然后，您可以像普通数组变量一样使用platformPkgs。

然后改变

            if [ "$pkgAction" == 'add' ]; then
                $pkgPlatform+=pkgName
                break

            elif [ "$pkgAction" == 'remove' ]; then
                unset "$pkgName"[$pkgPlatform]
                break

至

            if [ "$pkgAction" == 'add' ]; then
                platformPkgs+=( "$pkgName" )
                break

            elif [ "$pkgAction" == 'remove' ]; then
                ## not this => unset "platformPkgs[$pkgName]"
                # first, iterate through the array to find
                # the index for this value $pkgName,
                # then, unset "platformPkgs[$index]"
                # or rewrite the array except for the element at that index: 
                #   platformPkgs=( "${platformPkgs[@]:0:index}" "${platformPkgs[@]:index+1}" )
                break

Answer 2

您想要执行的第153行是

npmPkgs+=($pkgName)

但是在变量本身中有你的目标变量。请记住，shell的第一个爱好是构造命令行，变量替换只在您用$运算符指向它的地方完成。

用暴力的方法来做这件事

eval $pkgPlatform'+=($pkgname)'

这样做的目标名称替换，然后撤销结果行。

作为一个不相关的注释，您可以使用一些case语句来清理这个脚本。

Answer 3

您所面临的错误是因为您没有正确地将项附加到数组中，

$pkgPlatform+=pkgName ##that way the bash script can't get what you mean

因此，当您将一个项添加到变量pkgPlatform中时，可以这样做：

pkgPlatform+=("$pkgName")