bash - 如何制作 bash 脚本来检查程序或库是否存在

Question

我想创建一个函数来检查程序或库是否已经安装。

这就是我现在所做的:

dpkg --status software-properties-common | grep -q not-installed
if [ $? -eq 0 ]; then
    sudo apt-get install -y software-properties-common
fi

我想要的是:

isPackageNotInstalled() {???} 

if [ $(isPackageNotInstalled 'software-properties-common') ]; then 
   sudo apt-get install -y software-properties-common
fi

任何帮助将不胜感激。

Answer 1

一个示例脚本，包括一个检查和安装丢失包的函数:

#!/bin/bash

isPackageNotInstalled() {

    dpkg --status $1 &> /dev/null
    if [ $? -eq 0 ]; then
    echo "$1: Already installed"
    else
    sudo apt-get install -y $1
    fi
    }

isPackageNotInstalled $1

另存为script , 用法 ./script package_name .
man dpkg :

EXIT STATUS
       0      The requested action was successfully performed.  Or a check  or
              assertion command returned true.

       1      A check or assertion command returned false.

       2      Fatal  or unrecoverable error due to invalid command-line usage,
              or interactions  with  the  system,  such  as  accesses  to  the
              database, memory allocations, etc.