M4：如何从脚本后跟文件中删除前导空格？
M4: How to drop leading whitespace from script followed by file?
如果我有一个包含许多命令的 m4 脚本：
define(this, that)
define(or,this)
define(other,thing)
我打电话给：
$: m4 script.m4 my_file
输出为：
# N newlines for the N commands in the script
# first line of my file
是否可以在调用 m4 时抑制脚本读入产生的 N newlines，或者我是否必须将其包装在某些调用命令集（如 sed 或 grep)?
您可以使用 dnl 宏删除 define 的新行。例如。来自 this tutorial:
The define macro itself – including its two arguments – expands to an
empty string, that is, it produces no output. However the newline at
the end of the AUTHOR definition above would be echoed to the output.
If a blank line added to the output is a problem then you can suppress
it using the “delete to newline” macro:
define(AUTHOR, W. Shakespeare)dnl
There is no space between the end of the macro and the dnl: if there were
then that space would be echoed to the output.
如果我有一个包含许多命令的 m4 脚本：
define(this, that)
define(or,this)
define(other,thing)
我打电话给：
$: m4 script.m4 my_file
输出为：
# N newlines for the N commands in the script
# first line of my file
是否可以在调用 m4 时抑制脚本读入产生的 N newlines，或者我是否必须将其包装在某些调用命令集（如 sed 或 grep)?
您可以使用 dnl 宏删除 define 的新行。例如。来自 this tutorial:
The define macro itself – including its two arguments – expands to an empty string, that is, it produces no output. However the newline at the end of the AUTHOR definition above would be echoed to the output. If a blank line added to the output is a problem then you can suppress it using the “delete to newline” macro:
define(AUTHOR, W. Shakespeare)dnlThere is no space between the end of the macro and the dnl: if there were then that space would be echoed to the output.