Q:

shell script (with loop) to grep a list of strings one by one

I have a big data text file (more than 100,000 rows) in this format:
0.000197239;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=CLCNKA;GeneDetail.refGene=.;ExonicFunc
0.00118343;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=CLCNKA;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.00276134;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=CLCNKA;GeneDetail.refGene=.;
0.0607495;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=CLCNKA;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.00670611;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=XDH;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.000197239;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=XDH;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.000394477;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=GRK4;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.0108481;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=GRK4;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.000394477;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=GRK4;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;
0.0108481;AN=192;NS=2535;ANNOVAR_DATE=2015-12-14;Func.refGene=exonic;Gene.refGene=GRK4;GeneDetail.refGene=.;ExonicFunc.refGene=nonsynonymous_SNV;

Now, each row contains a gene name, such as in initial 4 rows there is CLCNKA gene. I am using grep command to count the frequency of each gene name in this data file, as:
grep -w "CLCNKA" my_data_file | wc -l

There are about 300 genes in a separate file which are to be searched in above data file. Can some expert please write a simple shell script with a loop to take gene name from a list one by one, and store its frequency in a separate file. So, the output file would be like this:
CLCNKA    4
XDH    2
GRK4    4

A:

You've confused us. I and some others think all you want is a count of each gene in the file since that's what your input/output and some of your descriptive text states (count the frequency of each gene name in this data file) which would just be this:
$ awk -F'[=;]' '{cnt[$11]++} END{for (gene in cnt) print gene, cnt[gene]}' file
GRK4 4
CLCNKA 4
XDH 2

while everyone else thinks you want a count of specific genes that exist in a different file since that's what your Subject line, proposed algorithm and the rest of your text states.
If everyone else is right then you'd need this tweak to read the "genes" file first and only count the genes in "file" that were listed in "genes":
awk -F'[=;]' 'NR==FNR{genes[$0]; next} $11 in genes{cnt[$11]++} END{for (gene in cnt) print gene, cnt[gene]}' genes file
GRK4 4
CLCNKA 4
XDH 2

Your example doesn't help since it would produce the same output with either interpretation of your requirements so edit your question to clarify what it is you want. In particular if there are genes that you do NOT want counted then include lines containing those in the sample input.

