我正在关注nix药丸[1]，在最新的频道发行版[2]中，该药不再起作用。
$ echo 'graph test { a -- b }'|result/bin/dot -Tpng -o test.png
Format: "png" not recognized. ...
因此，我建议使用旧频道[3]（并将binutils替换为binutils-unwrapped）。
nix-channel --add https://nixos.org/channels/nixpkgs-release-14.12
哪个效果很好？
nixpkgs https://nixos.org/channels/nixpkgs-unstable
nixpkgs-release-14.12 https://nixos.org/channels/nixpkgs-release-14.12
但是当我尝试通过import <nixpkgs-release-14.12>
我明白了
error: file 'nixpkgs-release-14.12' was not found in the Nix search path
答案 0 :(得分：1)
我通过
import (fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz)
有效，但我不确定这是否是最佳解决方案。
答案 1 :(得分：1)
您必须使用nix-channel --update命令下载它，但是由于删除了该频道，因此该命令不起作用。您必须使用较新的频道并运行--update。
答案 2 :(得分：0)
您可以通过在目录中使用git签出所需版本并设置package interest;
import java.util.Scanner;
public class Interest {
public static void main(String[] args) {
Scanner userInput = new Scanner(System.in);
Scanner whatKindPeriod = new Scanner(System.in);
double principle;
double rate;
double period;
double result;
double periodNumber;
String type;
String matOrSimp;
double matResult;
System.out.println("find maturity or simple interest? for simple interest enter simple, and for maturity enter maturity");
matOrSimp = userInput.next();
switch (matOrSimp) {
case "simple":
System.out.println("please enter the principle:");
principle = userInput.nextDouble();
System.out.println("Enter the rate:");
rate = userInput.nextDouble();
System.out.println("enter period:");
period = userInput.nextDouble();
System.out.println("is it daily, monthly or yearly?");
type = userInput.next();
switch (type) {
case "yearly":
result = (principle * rate * period) / 100;
System.out.println("your simple interest is: $" + result);
case "daily":
double daily = period / 365;
result = (principle * rate * daily) / 100;
System.out.println("your simple interest is: $" + result);
case "monthly":
double monthly = period / 12;
result = (principle * rate * monthly) / 100;
System.out.println("your simple interest is: $" + result);
SimpleInterest interest = new SimpleInterest(principle, rate, period);
}
case "maturity":
System.out.println("please enter the principle:");
principle = userInput.nextDouble();
System.out.println("Enter the rate:");
rate = userInput.nextDouble();
System.out.println("enter time of invesment:");
period = userInput.nextDouble();
double monthly = period / 12;
matResult = (principle * (1 + rate * monthly));
System.out.println("result is:" + matResult);
}
}
}
来实现。否则，它可能不可用和/或较新的频道中的其他软件包将取代它。您必须在NIX_PATH之前调用命令。