How can I extract a specific string from a file?

Question

I am having difficulties parsing my data. In the file shown below, I want to get the characters after BIG**20021208*00001**. I tried sed '/BIG.20021208.00001\**/!d;s///;s/\*.*//' but it doesn't work. I think the problem has to do with the line separator (…).

BIG*20021208*00001**A1001… 
TO*7284*0001…BIG*20021208*00001**A999… 
NN*ST*XYZ Test Corporation*9*122334455… 
NU*987 ELS.… 
N4**NY*98765… 
ITD*01*3*2**30**45*****60… 
N3*123 Highway Street… 
N4**12345… 
ITD*001*3*2**30**30*****60… 
BIG*20021208*00001**8263-83313… 
ITD*001*3*2**30**30*****60… 
BIG*20021208*00001**8263-83313… 

My expected output is:

A1001
8263-83313
8263-83313

Answer 1

There are many ways to do this. For example:

• grep

  grep -oP 'BIG\*20021208\*00001\**\K[A-Z0-9-]+' file
  

  Explanation

  The -o makes grep print only the matched portion of a line and the -P activates Perl Compatible Regular Expression (PCRE) syntax. The \K in PCREs causes whatever was matched up to that point to be discarded (and therefore not printed, because of -o). [A-Z0-9-] is a character class that matches any capital letter from A to Z, any number or - and which can be repeated one or more times (+).

  If your target strings can contain lower case letters as well, just run grep with the -i flag or change the character class to [a-zA-Z0-9-].

                                                            --- or ---

  grep -oP 'BIG\*20021208\*00001\**\K.+(?=…)' file
  

  Explanation

  This is just like the above only here, there's a positive lookahead ((?=…)) which means that .+ will only match if preceding a ….

• sed

  sed -rn 's/…//g;s/.*BIG\*20021208\*00001\**//p;' file
  

  Explanation

  The s/from/to/ is sed's substitution operator. It replaces from with to. The First one replaces … with nothing, it deletes them (the g ensures this is done for all matches on the line). The second deletes everything from the beginning of the line (.*) up to BIG*20021208*00001 (* has a special meaning in regular expressions so it needs to be escaped with \*), then 0 or more asterisks (\**). Combined, they delete everything except what you want.

  The -n suppresses printing of any output. The p at the end of the 2nd substitution operator causes sed to print any lies that where that substitution was successful.

• awk

  awk -F'[*…]' '/BIG\*20021208\*00001\**/{print $(NF-1)}' file
  

  Explanation

  The -F set's awk's input field separator to either * or …. This means that the penultimate field will be the one you want. The command above prints it on lines that match BIG*20021208*00001*.

• Perl

  perl -lne '/BIG\*20021208\*00001\**(.*)…/ && print "$1"' file
  

  Explanation

  The -n makes perl read its input line by line and apply the script given by -e to it. The -l adds a newline character to each print call. The command above will attempt to match the string of interest (see the explanation to the sed example above) and print it if successful.

  You could also use the same approach as in the awk example:

  perl -F'[*…]' -lane '/BIG\*20021208\*00001\**/ && print "$F[$#F]"' file
  

Answer 2

Using awk:

awk -F\* '/^BIG/ {gsub(/…/,""); print $NF}' file
A1001
8263-83313
8263-83313