使用xargs 让一列值，合成带分割的一行

admin

有时候我们需要将多行值，合并成一行：
测试命令如下:
cat b.txt |awk '{print $1}' |xargs
add-secgroup agent-create agent-delete agent-list agent-modify aggregate-add-host aggregate-cache-images aggregate-create aggregate-delete aggregate-list aggregate-remove-host aggregate-set-metadata aggregate-show aggregate-update availability-zone-list backup boot clear-password console-log delete diagnostics evacuate flavor-access-add flavor-access-list flavor-access-remove flavor-create flavor-delete flavor-key flavor-list flavor-show flavor-update force-delete get-mks-console get-password get-rdp-console get-serial-console get-spice-console get-vnc-console host-evacuate host-evacuate-live host-meta host-servers-migrate hypervisor-list hypervisor-servers hypervisor-show hypervisor-stats hypervisor-uptime image-create instance-action instance-action-list instance-usage-audit-log interface-attach interface-detach interface-list keypair-add keypair-delete keypair-list keypair-show limits list list-secgroup live-migration live-migration-abort live-migration-force-complete lock meta migrate migration-list pause quota-class-show quota-class-update quota-defaults quota-delete quota-show quota-update reboot rebuild refresh-network remove-secgroup rescue reset-network reset-state resize resize-confirm resize-revert restore resume server-group-create server-group-delete server-group-get server-group-list server-migration-list server-migration-show server-tag-add server-tag-delete server-tag-delete-all server-tag-list server-tag-set server-topology service-delete service-disable service-enable service-force-down service-list set-password shelve shelve-offload show ssh start stop suspend trigger-crash-dump unlock unpause unrescue unshelve update usage usage-list version-list volume-attach volume-attachments volume-detach volume-update bash-completion help --version --debug --os-cache --timings --os-region-name --service-type --service-name --os-endpoint-type --os-compute-api-version --os-endpoint-override --os-auth-type --insecure --os-cacert --os-cert --os-key --timeout --collect-timing --os-auth-url --os-system-scope --os-domain-id --os-domain-name --os-project-id --os-project-name --os-project-domain-id --os-project-domain-name --os-trust-id --os-default-domain-id --os-default-domain-name --os-user-id --os-username --os-user-domain-id --os-user-domain-name --os-password
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这样就完成了合成，有时候在某些地方需要标点符号，可以参考：
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