Prayer: What is the ruling on shaking hands right after prayer, given no narration exists but it promotes unity and affection?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: What is the ruling on shaking hands right after prayer, given no narration exists but it promotes unity and affection?

English:

Question #726:

What is your opinion concerning the praying persons doing shaking hands with each other immediately after the prayer? It is noteworthy that some eminent scholars have said that nothing is narrated on this subject from the Immaculate Imams (a.), and therefore there is no basis for shaking hands. But at the same time, we know that shaking hands increases friendship and affection among those who gather for prayer.

Answer #726:

There is no problem in shaking hands after the salām and finishing the prayer. In general, shaking hands with a believer is mustaḥabb.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer