Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
How to avoid command being saved to shell history
Answer:
Firstly, you need to set the Bash shell environment variable to tell the shell to ignore the history if the command is starting with a particular character, e.g. a space in our case below.
# export HISTIGNORE="&:[ ]*"
Then, type the command start with a space
# who
And verify using the history command
# history
Moving around with Bash short-cut
Answer:
Bash has some shortcuts that allow you to move around the command prompt
1. Ctrl + a
Just to the start of the current line.
2. Ctrl + e
Just to the endof the current line.
Repeat previous command in Bash
Answer:
It is easy to type !! when you want to repeat the previous executed command in Bash
# ls -l /var/log/messages
-rw-r----- 1 syslog adm 330 Mar 29 17:17 /var/log/messages
# !!
ls -l /var/log/messages
-rw-r----- 1 syslog adm 330 Mar 29 17:17 /var/log/messages
How to unset an environment variable in bash
Answer:
To unset an environment variable in bash, you can use the unset command.
Example:
# export foo=bar
# echo $foo
bar
# unset foo
# echo $foo
How to check the bash shell version
Answer:
To check the current bash shell version
# bash -version
GNU bash, version 3.2.48(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2007 Free Software Foundation, Inc.
