The first is the return status from a command, and the second is the trap command within your shell.

第一个是命令的返回状态，第二个是外壳中的trap命令。

youdao

A disposable non-woolen filter, and a panel type washable coarse aluminum filter are installed in the front panel of return air duct of each room, to trap powder generated, if any.

在每个房间回风管的前面板上安装有一台一次性的非毛织品过滤器，以及一台板式可洗粗铝过滤器，以捕捉收集可能产生的任何粉尘。

youdao

A check valve should be installed on return piping if there will be a pressurized return line or the trap drains to an overhead return line (Fig. B).

如果存在一个压力回路，或者疏水阀排放口位于回路管道的上方，则应该安装一个止回阀(图b)。

youdao

While the battle lines are being drawn, the scuttling little monster with the Peter Lorre wheedle leads Frodo and Sam toward a trap in order to steal the Ring before Frodo can finally return the damned thing to Mount Doom.

WSJ: Now That's an Epic