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

☞ x ≔ Cov ntaub ntawv tshiab: (Qhov chaw nyob /tmp: ‘a.txt’).
x sau ntawv: ‘123’.
✎ sau ntawv: x nyeem, tsum.
x txuas ntxiv: ‘345’.
✎ sau ntawv: x nyeem, tsum.
123
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