Bash variable delayed expansion?


 
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# 1  
Old 07-09-2010
Bash variable delayed expansion?

i write a batch file , here is the content.
Code:
dirname='date +%Y-%m-%d'
mkdir dirname

but it doen's work, it just create a folder named date and +%Y-%m-%d.
i have tried run the command seperately in the bash prompt. after the first
sentence executed , i use $dirname to watch the value of dirname ,it's right.
but how come mkdir command doesn't work?
# 2  
Old 07-09-2010
Code:
zra:/home/vbe $ dirname=$(date +%Y-%m-%d)
zra:/home/vbe $ echo $dirname            
2010-07-09

so
Code:
mkdir $dirname

after...
# 3  
Old 07-09-2010
How about ...

Code:
mkdir $dirname

... or "simply" ...

Code:
mkdir $( date '+%Y-%m-%d' )

# 4  
Old 07-09-2010
  1. To use the output of a command, use $(), or the older backticks `. Regular quotes won't work.
  2. Variables are used by prefixing them with a dollar symbol
This User Gave Thanks to pludi For This Post:
# 5  
Old 07-09-2010
thanks Mr. vbe and dr.House, i had a typo in my previous post, i do use 'mkdir $dirname'.

hi, pludi, your way works, thanks very much .
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