CODEWITHSUNDEEP
bashvariablesawksave
hasdenkt
hasdenkt

Reputation: 11

Unix: awk save values as variable

I have a filename with several underscores:

nc_glals_3_4.mrc

and there I can read out the values 3 and 4 with awk:

$ echo "nc_glals_3_4.mrc" | awk -F'[_.]' '{print$3$4}' 
34

But if I like to store 34 as a variable and recall the variable, it does not work:

$ variable=$("nc_glals_3_4.mrc" | awk -F'[_.]' '{print $3$4}')
-bash: nc_glals_3_4.mrc: command not found

$ variable="$("nc_glals_3_4.mrc" | awk -F'[_.]' '{print $3$4}')"
-bash: nc_glals_3_4.mrc: command not found

$ variable
-bash: variable: command not found

What's wrong?

Upvotes: 1

Views: 144

Answers (3)

louigi600
louigi600

Reputation: 743

If the numbers you want to retain are always in the same position:

test@darkstar:~$ Filename="nc_glals_3_4.mrc"
test@darkstar:~$ awk -F'[_.]' '{print$3$4}' <<< $Filename
34
test@darkstar:~$ Numbers=$(awk -F'[_.]' '{print$3$4}' <<< $Filename)
test@darkstar:~$ echo $Numbers
34
test@darkstar:~$

But if the numbers are not always in the same position and you want to catch all numbers between underscores or between underscore and full stop no matter where they occour:

Numbers=$(awk -F'[_.]' '{for (i=0;i<=NF;i++) {if ($i~/^[0-9]+$/) {printf("%i", $i)}}}' <<< $Filename)

Upvotes: 2

markp-fuso
markp-fuso

Reputation: 34024

Just as you used echo on the command line, you also need to use echo in the sub-process call, eg:

# wrong:

$ variable=$("nc_glals_3_4.mrc" | awk -F'[_.]' '{print $3$4}')

# right:

$ variable=$(echo "nc_glals_3_4.mrc" | awk -F'[_.]' '{print $3$4}')

# or using here string:

$ variable=$(awk -F'[_.]' '{print $3$4}' <<< "nc_glals_3_4.mrc")

Then use echo again to display the variable's value:

$ echo "${variable}"
34

Upvotes: 1

giovannipa
giovannipa

Reputation: 21

If I understand your question:

variable=$(echo "nc_glals_3_4.mrc" | awk -F'[_.]' '{print $3$4}')

You need an echo in your command.... now '34' is stored into variable.

Upvotes: 1

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