CODEWITHSUNDEEP
awk
pogibas
pogibas

Reputation: 28339

Awk: Using invert match to a string and then substitute characters

I want to extract lines that don't contain # and delete ", ; in the output.

My input FILE looks like this:

# ;string"1"
# string"2"; 
string"3";

Can use grep and tr to get wanted output:

grep -v '#' FILE | tr -d ';"'  
string3

However I want to use awk.

I can extract invert match awk '!/#/' FILE, but how can I use sub to delete ", ; in the same awk command?

Upvotes: 7

Views: 12206

Answers (4)

paxdiablo
paxdiablo

Reputation: 881563

You can use gsub for global substitution:

awk '!/#/{gsub(/[";]/,"",$0);print}'

The following transcript shows this in action, it delivers the same results as your grep/tr pipeline:

pax> echo '# ;string"1"
# string"2"; 
string"3";' | awk '!/#/{gsub(/[";]/,"",$0);print}{}'

string3

Note that the final {} may not be necessary in some implementations of awk but it's there to stop output of non-matching lines in those implementations (usually older ones) that do it automatically for lines matching none of the rules.

Upvotes: 5

konsolebox
konsolebox

Reputation: 75488

Use gsub instead which would replace all matches not just one:

awk  '/#/{next}{gsub(/[";]/,"")}1' file

Output:

string3
  • Skipping the third parameter to gsub makes it process $0 by default.
  • /#/{next} makes it skip lines containing #
  • 1 makes it print $0

Upvotes: 3

anubhava
anubhava

Reputation: 785196

If you want to give sed a chance:

sed -n '/^[^#]/s/[";]//gp' file
string3

Upvotes: 2

Jotne
Jotne

Reputation: 41456

Another awk version

awk -F"[\";]" '{$1=$1} !/^#/' OFS= file
string3

awk  '{gsub(/[";]/,x)} !/^#/' file
string3

The x represents nothing. Could also have used "", but saves one characters :)

Upvotes: 2

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