Makefile顺序执行

Question

我有以下 Makefile:

all: generate print # <-- doesn't work

date: 
    date > date.txt

ls:
    ls -la > ls.txt

generate: ls date

print: *.txt
    cat $^

clean:
    rm *.txt

目标date和ls分别生成一个文件，目标print将它们打印出来。

如何编写目标全部，以便它首先生成文件，然后然后打印它？

Answer 1

只需添加管道符号:

all: | generate print

来自make manual :

Order-only prerequisites can be specified by placing a pipe symbol (|) in the prerequisites list: any prerequisites to the left of the pipe symbol are normal; any prerequisites to the right are order-only:

targets : normal-prerequisites | order-only-prerequisites