#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)^(\S+)[^\S\r\n]+"
Local $sString = "GAXI01000525.151.1950 Eukaryota;Opisthokonta;Holozoa;Metazoa (Animalia);Eumetazoa;Bilateria;Arthropoda;Hexapoda;Ellipura;Collembola;Tetrodontophora bielanensis (giant springtail)" & @CRLF & _
"GAXI01000526.151.1950 Eukaryota;Opisthokonta;Holozoa;Metazoa (Animalia);Eumetazoa;Bilateria;Arthropoda;Hexapoda;Ellipura;Collembola;Tetrodontophora bielanensis (giant springtail)" & @CRLF & _
"GAXI01005455.1.1233 Bacteria;Bacteroidetes;Flavobacteriia;Flavobacteriales;Flavobacteriaceae;Chryseobacterium;Tetrodontophora bielanensis (giant springtail)" & @CRLF & _
"GAXI01006199.29.1525 Bacteria;Chlamydiae;Chlamydiae;Chlamydiales;Simkaniaceae;Candidatus Rhabdochlamydia;Tetrodontophora bielanensis (giant springtail)"
Local $sSubst = "$1;"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm