awk - concatenate two string variable and assign to a third

Question

In awk  I have 2 fields   1 and  2   They are both strings that I want to concatenate and assign to a variable

User · Answer

Concatenating strings in awk can be accomplished by the print command AWK manual page, and you can do complicated combination. Here I was trying to change the 16 char to A and used string concatenation:

echo    CTCTCTGAAATCACTGAGCAGGAGAAAGATT | awk -v w=15 -v BA=A '{OFS=""; print substr($0, 1, w), BA, substr($0,w+2)}'
Output: CTCTCTGAAATCACTAAGCAGGAGAAAGATT

I used the substr function to extract a portion of the input (STDIN). I passed some external parameters (here I am using hard-coded values) that are usually shell variable. In the context of shell programming, you can write -v w=$width -v BA=$my_charval. The key is the OFS which stands for Output Field Separate in awk. Print function take a list of values and write them to the STDOUT and glue them with the OFS. This is analogous to the perl join function.

It looks that in awk, string can be concatenated by printing variable next to each other:

echo xxx | awk -v a="aaa" -v b="bbb" '{ print a b $1 "string literal"}'
# will produce: aaabbbxxxstring literal

User · Answer

You can also concatenate strings from across multiple lines with whitespaces    cat file txt apple 10 oranges 22 grapes 7  Example 1  awk   aggr aggr  quot   quot   2  END  print aggr   file txt 10 22 7  Example 2  awk   aggr aggr  quot    quot   1  quot   quot   2  END  print aggr   file txt   apple 10  oranges 22  grapes 7

User · Answer

Just use var   var1 var2 and it will automatically concatenate the vars var1 and var2  awk   new var  1 2  print new var   file  You can put an space in between with  awk   new var  1 quot   quot  2  print new var   file  Which in fact is the same as using FS  because it defaults to the space  awk   new var  1 FS  2  print new var   file  Test   cat file hello how are you i am fine   awk   new var  1 2  print new var   file hellohow iam   awk   new var  1 FS  2  print new var   file hello how i am  You can play around with it in ideone  http   ideone com 4u2Aip

User · Answer

Could use sprintf to accomplish this   awk   str   sprintf   s  s    1   2   END  print str   file

[awk] awk - concatenate two string variable and assign to a third

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