#!/bin/bash
s="TRINITY_DN66807_c0_g1_i1	4	*	0	0	*	*	0	0	TTTAAGAAAATTACAGCCTGAACTAGATGAATTGCAAAAACTCATAGGCAAAAAGGAAGAAGAAATTGGATACGT	*
    TRINITY_DN66871_c0_g1_i1	4	*	0	0	*	*	0	0	AAGAGGACATAGAAACTGTGATGATAATAGTATTGCTCTACTATTTCCTATAGCTCAGTTATTCAGCTGTCAGTC	*
    TRINITY_DN66847_c0_g1_i1	0	38	2520299	37	274M	*	0	0	CTCTCCTAGGATGCAGGATGGCCTCTTGCCACCTACACCCTTCTTCATGGGTTCGGCCCTTGGTCAACTAAAGGA	*	XT:A:U	NM:i:0	X0:i:1	X1:i:0	XM:i:0	XO:i:0	XG:i:0	MD:Z:274
    TRINITY_DN66836_c0_g1_i1	0	38	21725268 37	733M	*	0	0	TAGATGATGAAACTGGGTTGACCCTTGTTCCTAAGACTCAGTCCAGAGAGTCCTGGACTTTGCACTTTGGTTAGATGCCCCTGCCCCTCCCGCCAGCGCTGAGGAGGAATCACGCAGGCCTGAACAGAACATTCAGGTGATCCTATGAAG	*	XT:A:U	NM:i:0	X0:i:1	X1:i:0	XM:i:0	XO:i:0	XG:i:0	MD:Z:733"
 
awk '$3 ~ /^38$/' <<< "$s"

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