[root@linux-node1 ~]# cat test.txt
1001 hisk01
1001 hisk02
1001 hisk03
1002 hisk04
1002 hisk05
1002 hisk06
1003 hisk07
1003 hisk08
[root@linux-node1 ~]# awk '{if($1==x){i=i" "$2}else{if(NR>1){print i};i=$0};x=$1;y=$2}' test.txt <(echo)
1001 hisk01 hisk02 hisk03
1002 hisk04 hisk05 hisk06
1003 hisk07 hisk08
[root@linux-node1 ~]# awk '{a[$1]=a[$1]?a[$1]" "$2:$2}END{for(i=0;i++<asorti(a,b);)print b[i],a[b[i]]}' test.txt
1001 hisk01 hisk02 hisk03
1002 hisk04 hisk05 hisk06
1003 hisk07 hisk08
[root@linux-node1 ~]#
$ cat ip_test.txt
192.0.0.1 test02
192.0.0.2 test03
192.0.0.1 test02
192.0.0.3 test04
192.0.0.2 test02
192.0.0.1 test02
192.0.0.1 test02
$ awk '{ip[$1]=ip[$1]" "$2} END {for(i in ip) print i, ip[i]}' ip_test.txt
192.0.0.3 test04
192.0.0.1 test02 test02 test02 test02
192.0.0.2 test03 test02
