Knowing your history

Shells provide an interesting feature that allows you to find out the history of all commands you have executed previously in a shell. It often happens that we forget what command was typed on the previous day to perform a task. We may or may not be able to recall the exact syntax, but it is very convenient that we can refer to the history saved by the shell.

Shell variables controlling the history

There are shell variables that can be altered to change what and how much history a user can see. These shell variables are mentioned in the following table:

Name	Value
HISTFILE	Name of file in which by default history will be saved
HISTFILESIZE	Number of commands to be kept in history file
HISTSIZE	Number of history to be stored in memory for current session
HISTCONTROL	A colon-separated list of values controlling how commands are saved on the history list

The value of the HISTCONTROL shell variable can be:

Value	Description
ignorespace	Lines which starts with a...