unix - Unlimited Bash History - Stack Overflow Set HISTSIZE and HISTFILESIZE to an empty string: HISTSIZE= HISTFILESIZE= In  you can also use HISTSIZE=-1 HISTFILESIZE=-1:

n.  Setting HISTSIZE to a value less than zero causes the history list to be unlimited (setting it 0 zero disables the history list). o. Setting HISTFILESIZE to a value less than zero causes the history file size to be unlimited (setting it to 0 causes the history file to be truncated to zero size).