question about define variable.


 
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# 1  
Old 01-26-2012
question about define variable.

Hi, Unix Gurus,
In our existing file, there is a script like

Code:
#!/bin/sh
step=${1:-0}
cur_step=10
if [ $step -le $cur_step ]

...
My question is what's "${1:-0}" mean? I know it defines a variable but I don't know what's (1:-0) mean?

Smilie

Thanks in advance.
ken002
# 2  
Old 01-26-2012
If $1 isn't set, it becomes 0.
This User Gave Thanks to Corona688 For This Post:
# 3  
Old 01-26-2012
Quote:
Originally Posted by Corona688
If $1 isn't set, it becomes 0.
Thanks for you quick reply.
Smilie
ken002
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