shell - 在 csh 脚本中设置默认用户变量

Question

我正在编写一个 csh shell 脚本，run用户应该在其中将路径作为$1变量传递给它。如何确定是否$1丢失并为其定义默认值？

Answer 1

This is know to work on tcsh version 6.15.00

#! /bin/csh

if( $#argv == 0 ) then
        set filename="(default file)"
else
    set filename=$argv[1]
endif

echo "The file is $filename."

NOTE
There is no standard with csh as there is with the POSIX shell; but at least basic if-then-else and $#argv should be portable.

See Also
POSIX and Korn Shell Versus Other Shells
Csh Programming Considered Harmful
Bash

Answer 2

您可以执行以下操作：

if [ $# -eq 0 ];then
        dir='default' # argument not passed use default.
else
        dir=$1        # argument passed..use it.
fi

# use $dir 
ls $dir