Awk previous day -

for reason can not work? want compare previous day , current days file.

awk 'fnr==nr{a[nr]=$2;next}{print $1,$2-a[fnr]}' router_evi_`(strftime("%y-%m-%d", systime()-86400))`.txt router_evi_`(date +"%y-%m-%d")`.txt > temp_plus_minus.txt 

thanks

you confused awk script , shell's $(..) or

`...` 

the command gave is:

awk '....' foo_`(awkcode)`.txt bar_`(shell cmd)`.txt                     ^ ---problem----------| 

this won't work. since cannot let shell interpret , execute awk code. should write shell command/code in backticks. or this:

foo_$(awk 'begin{print strftime("%y-%m-%d", systime()-86400)}').txt 

it better getting 2 filenames in variables first(if dynamic), , call awk script. making 1 line not best solution.