shell command

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Command to the ~./bash_logout so that the history will get cleared when you logout

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echo `history -c` >> ~/.bash_logout

Get the name of the history file

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echo "$HISTFILE"

See the current history

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history
history | grep 'du'

Hide and display the cursor in the shell

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# Hide the cursor
echo -e "\033[?25l"

# Display the cursor
echo -e "\033[?25h"

Three ways of multiple line annotation

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:<<EOF
annotation text...
annotation text...
annotation text...
EOF

:<<'
annotation text...
annotation text...
annotation text...
'

:<<!
annotation text...
annotation text...
annotation text...
!

Make file executable

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chmod +x <file.name>

Use math equation in shell script (example)

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#!/bin/bash

val=`expr 2 + 2`
echo "sum of two numbers: $val"

Operators in shell script

Enable interpretation of the backslash escapes

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echo -e

Read varable and assign to a variable <variable.name>

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read <variable.name>

vi/vim language and affiliated shortcuts

Shell I/O redirection

Reference