Awk script problem - Variables Causing Issue

Shell Programming and Scripting
1

can someone please explain to me what i'm doing wrong with this code:

WELT=$(awk '(($1 ~ "^${caag}$") || ($2 ~ "^${caag}$"))' /tmp/Compare.TEXT)

when run from the command line, it works. but it seems to be having a problem doing the comparison when variables are involved.

i tested from the command line and assigned a value to "caag", it wouldn't work.

but when i just replaced caag on the command line with the actual value, it passes.

i've been stalled all day by this. any help will be much appreciated.

2

Variables do not expand inside single quotes:

$ echo '${HOME}'
${HOME}

$

Awk has better means to pass variables than embedding them in the string, fortunately:

WELT=$(awk -v CAAG="^${caag}\$" '(($1 ~ CAAG) || ($2 ~ CAAG))' /tmp/Compare.TEXT)

If awk complains about this syntax, try nawk. Some systems keep a very old awk around for compatibility reasons.

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