Using the Bash Shell
Bash is a Unix shell written by Brain Fox for the GNU Project as a Free Software replacement for the Borne Shell(sh).Released in 1989, it has been distributed widely as the shell for the GNU Operating System and as a default shell on Linux and MAC OS X.
Command Line Shortcuts:
Globing is wildcard expansion:-
Option
|
Description
|
Example
|
*
|
matches zero or more
characters
|
# rm *mp3
all files in the directory have names ending in mp3 will be removed |
?
|
matches any single
character
|
#echo ?o*
|
{0-9}
|
matches a range of
numbers
|
#ls -l {1,2,3,4}
it display all the
files matches the list.
|
tab to complete command lines: for the command name, it will complete a command name for an argument, it will complete a file name
examples:
#cle
#clear
#ls myfi
#ls myfile.txt
History:
1. bash stores a history of the commands you have entered, which can be used to repeat commands
2. use history command to see list of "remembered" commands
examples:
#history
#!! repeat last command
#!char repeats last command that start with char
#!num repeat a command by its number in history output
#!?abc repeats last command that contains abc
#!-n repeat a command entered n command back use ^old^new to repeat the last command with old change to new
#cp myfil.txt /aa/bb/cc
#^myfil.txt^myfile.txt
more history tricks-
1. use the up and down keys to scroll through previous commands
2. type Ctrl-r to search for a command in command history
to recall last argument from previous command:
Esc. (the Escap key followed by a period)
Alt-. (hold down the alt key while pressing the period)
!$ (only valid for the last command)
Command Line Expansion-
Tilde (~)
May refer to your home directory
#cat ~/filename
2. May refer to another user's home directory
#ls -l ~john/filename
Command and Braced sets:
1. command Expansion: $() or ``
prints output of one command as an argument to another
#echo "this system's name is $(hostname)"
#echo this system's name is `hostname`
2. Brace Expansion: { }
#echo file{1,2,3}
#rm -f file{1,2,3}
Bash Variables-
1. variables are named values useful for storing data or command output
2. set with VARIABLE=VALUE
#x=5
3. referenced with $VARIABLE
example:
#HI="Hello, and Welcome to the IIJT Computer Education Ltd"
#echo $HI
Command Editing tricks
1. Ctrl+a moves to beginning of line
2. Ctrl+e moves to end of line
3. Ctrl+u deletes to beginning of line
4. Ctrl+k deletes to end of line
5. Ctrl_arrow moves left or right word
gnome terminal-
1. Application->Accessories->Terminal
2. Graphical terminal emulator that supports multiple "tabbed" shells.
1. Ctrl+shift+t create a new tab
2. Ctrl+pgup/pgdn switch to next/prev tab
3. Ctrl+Shift+c copies selected text
4. Ctrl+Shift+v pastes text to the prompt
5. Shift+pgup/pgdn Scroll up and down a screen at a time
Scripting Basic-
1. shell scripting are text files that contain a series of commands or statement to be executed.
2. shell scripting are useful for:
1. automating commonly used command
2. performing system administration and troubleshooting
3. creating simple applications
4. manipulating or text or files.
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