Annotation:
keep an eye out for something/someone (idiom) means to watch with special attention for something/someone.
Watch for someone — does it mean here that
1) pay attention so that that person doesn't do anything bad,
or
2) wait until that person appears
or
3) take care of that person
?
It could not mean 1) or 3) but could mean 2).
The implication is that the appearance of the postman is important to the speaker as they are probably awaiting a letter, parcel etc. You could add something like "and let me know when you see him" to the end of the sentence.
Thanks, now I can translate it to Russian.
Edit: It was quite tough to do!
گالد ئے نبشت
لیسن: CC BY 2.0 FRلاگ
اے گالِد بُندَری یے ءُ چہ رجانک ءَ زیرگ نہ بیتگ۔
ءِ گیش کرتگینpatgfisher،April 16, 2014
ءِ کڑی کرتگینInego،April 16, 2014
ءِ کڑی کرتگینduran،July 4, 2016