linux - Inline variable in shell script -

in 1 of requirement, create command @ start of script , fill variable later. example:

# global mylistdir="ls -la $mydair"  #now after code  want create variable mydair="/data/dir/" #now run taht command on /data/dir echo "$mylistdir"

how can it?

i tried

mylistdir="ls -la `$mydair`"`

but didn't work.

code should stored in functions, not variables. see bashfaq #50 full description of rationale, , bugs caused ignoring rule.

mylistdir() { ls -la "$mydair"; } mydair=/data/dir mylistdir

if absolutely must store code in variable, use eval:

mylistdir='ls -la "$mydair"' mydair=/data/dir eval "$mylistdir"

...but mind caveats given in bashfaq #48.

the original code proposed in question written follows:

mylistdir="ls -la `$mydair`"`

...now, that's broken several reasons:

it uses double-quotes on outside, causing expansions performed @ assignment time instead of @ later evaluation time.
it puts backticks around $mydair, causing value of variable as exists @ assignment time string-split, glob-expanded, , run command, output of command (presumably, empty string) substituted in place.
it has trailing, unmatched backtick @ end, making invalid syntax.

Ben