[英]what does the following “$?run” mean in shell csh
What $?run
does in the following example? 在以下示例中,
$?run
是什么? run
is variation with run
directory. run
是run
目录的变体。 I understand that $?
我了解
$?
has the status of the last command. 具有最后一条命令的状态。
if ( ! $?run ) then
set run = $PWD
endif
You can use $?var_name
to check if a variable is defined. 您可以使用
$?var_name
检查是否定义了变量。 From man csh
: 来自
man csh
:
$?name
${?name}
Substitutes the string `1' if name is set, `0' if it is not.
This is not the same as the special $?
这是不一样的特殊
$?
variable (yeah, the syntax is a bit confusing). 变量(是的,语法有点混乱)。
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