Matching text using grep or awk

Question

I am having problems with grep and awk. I think it\'s because my input file contains text that looks like code.

The input file contains ID names and looks like this:

Answer 1

This was a nice bashish try. The problem was that You always overwrite the result file. Use '>>' instead of > or move the > after done

grep -w $line reference.file >> outputfile

or

done  > outputfile

But I would prefer Lev's solution as it starts an external process only once.

If You want to solve it in pure bash, you could try this:

ID=($(outputfile

cat outputfile

Output:

ENSG00000199537 SNORD115-40
ENSG00000207793 MIR432
ENSG00000207447 RNU6-2

Newer bash supports associative arrays. It can be used to simplify and speed up the search for a key:

declare -A ID
for i in $(