awk 脚本不是运行中间块

Question

以下脚本只会运行 BEGIN 和 END 块：

#!/bin/awk -f

BEGIN {print "Hello, World!"}
{ print "Don't Panic" }
END { print "and we're panicking... I told you not to panic.  Did you miss that part?" }

输出为：

$ awk -f joint.awk .
  Hello, World!
  and we're panicking... I told you not to panic.  Did you miss that part?

预期输出是：

$ awk -f joint.awk .
  Hello, World!
  Don't panic
  and we're panicking... I told you not to panic.  Did you miss that part?

奇怪的是，当我将中间块更改为 print ，而不是打印一段文本时，当我传入一个文件时，它运行符合预期。

Answer 1

在 stdin 上（或在您的输入文件中，如果明确命名的话），没有明确条件的内行得到运行 一次。

因此，打印多少次Don't Panic取决于有多少输入。

查看通过以下代码测试的内容：

awkScript=$(cat <<'EOF' BEGIN {print "Hello, World!"} { print "Don't Panic" } END { print "and we're panicking... I told you not to panic. Did you miss that part?" } EOF ) echo "Testing with no input:" awk "$awkScript" </dev/null echo echo "Testing with one line of input:" awk "$awkScript" <<<"One line of input" echo echo "Testing with two lines of input:" awk "$awkScript" <<<$'First line\nSecond line'

...作为输出发出：

Testing with no input: Hello, World! and we're panicking... I told you not to panic. Did you miss that part? Testing with one line of input: Hello, World! Don't Panic and we're panicking... I told you not to panic. Did you miss that part? Testing with two lines of input: Hello, World! Don't Panic Don't Panic and we're panicking... I told you not to panic. Did you miss that part?

awk 脚本不是 运行 中间块

awk script is not running the middle block

awk

awk 脚本不是运行中间块