CODEWITHSUNDEEP
bashshellawk
zeushvk
zeushvk

Reputation: 11

Cut a string between two variable sub strings in shell

I have filenames as below(omitted the actual names) I need to extract the filename between the filename_prefix and runid Problem here being the filename changes and is 2-5 fields long. I have been using this 

echo "filename_prefix_filename_filename_filename_runid_date_part-r-00020-c68fdc43-53bc-4aa9-a96b-2692ae2aa508.orc " | awk 'NR > 1 {print $1}' RS='filename_prefix' FS='runid'

This works fine on the command line but I need to pass RS and FS as variables which I am not able to do so because

echo of file name |awk -v file_p=$file_prefix -v r_id=_$RUN_ID 'NF > 1 {print $1}' RS=file_p FS=r_id

the above command doesn't work.

Filenames:

filename_prefix_filename_filename_filename_runid_date_part-r-00020-c68fdc43-53bc-4aa9-a96b-2692ae2aa508.orc

filename_prefix_filename_filename_runid_date_part-r-00020-c68fdc43-53bc-4aa9-a96b-2692ae2aa508.orc

Upvotes: 0

Views: 253

Answers (3)

karakfa
karakfa

Reputation: 67567

you can do the same in bash, although a two step process

$ f="filename_prefix_filename_filename_filename_runid_date_part-r-00020-c68fdc43-53bc-4aa9-a96b-2692ae2aa508.orc"; 
  pre="filename_prefix_"; 
  run="_runid*";

$ ff=${f%$run}; echo ${ff#$pre}

filename_filename_filename

Upvotes: 1

tripleee
tripleee

Reputation: 189948

The assignments to RS and FS are wrong. You cannot use Awk variables here; they are interpreted simply as static strings (which is the only arrangement which makes sense anyway).

awk 'NF > 1 {print $1}' RS="$file_prefix" FS="_$RUN_ID"

Upvotes: 1

chepner
chepner

Reputation: 532538

Because you are still setting RS and FS outside the awk script itself, you use the shell variable, not awk variables.

... | awk 'NF > 1 {print $1}' RS="$file_prefix" FS="$RUN_ID"

Alternately, you can use

... | awk -v RS="$file_prefix" -v FS="$RUN_ID" 'NF > 1 {print $1}'

or

... | awk -v file_p="$file_prefix" -v runid="$RUN_ID" 'BEGIN{RS=file_p; FS=runid}; NF > 1 {print $1}'

The last one, though, is unnecessarily indirect.

Upvotes: 1

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