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ksh: what does var=$(command) mean?

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# 1  
Old 10-26-2010
ksh: what does var=$(command) mean?
hi,

i can see in a script

it contains

Code:
var=$(
         myFile | grep -i err
)

why has this person done it like this? why not just

Code:
var=`myFile | grep -i err`

thanks
# 2  
Old 10-26-2010
Well, '`' is small (hard to see/discern from "'"), vi '%' does not pair them, and it
does not nest. I am not sure if it swallows linefeeds -- probably. So, good style is to use ksh and $(). Also, use closed paren pairs in 'case' so they stay in balance for vi '%'.
This User Gave Thanks to DGPickett For This Post:
JamesByars
# 3  
Old 10-26-2010
backtick `` means pass the result as a variable in old fashion
Using $() is new fashion (some shell implementation may not support this way to write things
This User Gave Thanks to ctsgnb For This Post:
JamesByars
# 4  
Old 10-26-2010
thanks guys
# 5  
Old 10-26-2010
Yes, $() is not supported in bourne shell (sh).
# 6  
Old 10-26-2010
Solaris' /bin/sh is one shell in a current OS that keeps popping up that does not support $() . But you can use /usr/xpg4/bin/sh instead ...
# 7  
Old 10-26-2010
Note that, at least as far as ksh93 is concerned, there is a subtle difference between command substitution using $(...) and command substitution using `...`. In the second (obsolute) form, the string between the quotes is processed for special quoting characters before the command is substituted.
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