[ Cov-ntaub-ntawv ] txuas-ntxiv: [ Ntawv-nyeem ]

var x := Cov-ntaub-ntawv tshiab: (Qhov-chaw-nyob /tmp: ['a.txt']).
x sau-ntawv: ['123'].
Stdout sau-ntawv: x nyeem, tsum.
x txuas-ntxiv: ['345'].
Stdout sau-ntawv: x nyeem, tsum.
123
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