Setting awk to variable - bash

Question

I have code that looks like this:
awk -F'|' '{if($1 in a)print "duplicate found:" $2 " AND "a[$1];else a[$1]=$2 }' dump.txt
I need to set $2 and a[$2] to a variable. How would I go about doing this?
I am taking a file that contains: a value "|" filename and then I want to set the filename and the value to two different variables.

Answer 1

What do you mean Set those variables? Are these environment variables. In Awk, variables that start with a dollar sign and are numeric are reserved for AWK. These are the field values for each line. For example:
test.txt =
this is line one
this is line two
this is line three
The command awk '{print $4}' test.txt will print out the fourth field:
$ awk '{print $4}' test.txt
one
two
three
$ awk '{print $3}' test.txt
line
line
line
As you can see: They don't have to be set. They're automatically set by Awk.
If you want to set environment variables, you can use the -v parameter
awk -v search="foo" '{
if (search = $1) {
print "Found your string in record " NR
}'
In the above, search is an Awk variable that is set equal to foo.
Since Awk is a programming language, it is sometimes easier to see what's going on by correctly formatting your program:
awk -F'|' '{
if($1 in a) {
print "duplicate found:" $2 " AND " a[$1]
}
else {
a[$1] = $2
}
}' dump.txt
The program is taking each line. Each line consists of two parts separated by the |. It appears that the first part in the key and the second part is the data. I've created a text file that looks like this:
This is a|test
That is a|line
who moans for|anchovies
whom moans for|anchovies
This is a|test again
The first and last line should show up as duplicates
I took your program and added a few debug lines. This will help me trace where it is in your program:
awk -F\| '{
if ($1 in a) {
print "DEBUG: In If clause"
print "duplicate found:" $2 " and " a[$1]
} else {
print "DEBUG: In else clause"
a[$1] = $2
print "DEBUG: a[" $1 "] = " a[$1]
}
print "DEBUG: $1 = " $1
print "DEBUG: $2 = " $2 "\n"
}' test.txt
And, this is my output
DEBUG: In else clause
DEBUG: a[This is a] = test
DEBUG: $1 = This is a
DEBUG: $2 = test
DEBUG: In else clause
DEBUG: a[That is a] = line
DEBUG: $1 = That is a
DEBUG: $2 = line
DEBUG: In else clause
DEBUG: a[who moans for] = anchovies
DEBUG: $1 = who moans for
DEBUG: $2 = anchovies
DEBUG: In else clause
DEBUG: a[whom moans for] = anchovies
DEBUG: $1 = whom moans for
DEBUG: $2 = anchovies
DEBUG: In If clause
duplicate found: test again and test
DEBUG: $1 =This is a
DEBUG: $2 = test again
Taking out the debug lines:
awk -F\| '{
if ($1 in a) {
print "duplicate found:" $2 " and " a[$1]
} else {
a[$1] = $2
}
}' test.txt
duplicate found: test again and test
As they say:
IT WORKS ON MY COMPUTER
(rimshot)
Seriously, what is your program suppose to be doing, and what do you see it do? Are there any errors? Your program appears to work as advertised.

Answer 2

Set them to an environment variable like this:
awk -F'|' '{if($1 in a)print "duplicate found:" '"$2"' " AND "a[$1];else a[$1]='"$2"' }' dump.txt
Note that what I did was to "disable" the single-quotes around the $2 parts, and add double-quotes around them in case the environment variable contains spaces (which awk wouldn't want to see splitting its argument into pieces).