mirror of
https://github.com/autistic-symposium/shell-whiz-toolkit.git
synced 2025-05-12 19:52:14 -04:00
97 lines
No EOL
1.9 KiB
Markdown
97 lines
No EOL
1.9 KiB
Markdown
Wild Cards
|
|
----------
|
|
|
|
Use *, ? (for one char), and [abc] for a series of options. Example:
|
|
|
|
$ ls [abc]*
|
|
|
|
|
|
More commands on one line
|
|
-------------------------
|
|
|
|
Use ;
|
|
$ date;who
|
|
|
|
|
|
Redirection of Standard output/input
|
|
-----------------------------------
|
|
|
|
>, >>, <
|
|
|
|
Examples:
|
|
|
|
$ sort < filename > sorted_names
|
|
|
|
|
|
Pipes
|
|
-----
|
|
A pipe is nothing but a temporary storage place where the output of one command is stored and then passed as the input for second command.
|
|
|
|
|
|
Processes and PID
|
|
-----------------
|
|
An instance of running command is called process and the number printed by shell is called process-id (PID), this PID can be use to refer specific running process.
|
|
|
|
ps - show current running
|
|
kill {PID} - kill process
|
|
kill 0 - stop all processes except shell
|
|
& - background process
|
|
ps aux - display the owner of the processes along with the processes
|
|
ps -ag - get information of all running processes
|
|
ps ax | grep processes-you-want-to-see
|
|
top - see currently running processes and other information like memory and CPU
|
|
pstree - display a tree of processes
|
|
|
|
|
|
|
|
Useful Cmds:
|
|
------------
|
|
|
|
List size of folders
|
|
$ du -sh *
|
|
|
|
Print calendar:
|
|
$ cal
|
|
|
|
Writing and creating a file:
|
|
$ cat > NEWFILE
|
|
|
|
--- write here ---
|
|
^D
|
|
|
|
|
|
De-bug Shell Script
|
|
-------------------
|
|
|
|
Use -v and -x option:
|
|
$ sh option SCRIPT
|
|
$ bash option SCRIPT
|
|
|
|
|
|
Local and Global Variables
|
|
-------------------------
|
|
|
|
Whenever you type:
|
|
$ /bin/bash
|
|
You start a new shell where the previous variables will be forgotten (local variables). To make variables global, you can do:
|
|
$ export VARIABLE-NAME
|
|
Before changing shell.
|
|
|
|
|
|
Conditional Execution
|
|
---------------------
|
|
|
|
The control operators are && (AND) and || (OR).
|
|
$ rm myf && echo "File is removed successfully" || echo "File is not removed"
|
|
|
|
|
|
Functions
|
|
---------
|
|
|
|
$ SayHello()
|
|
{
|
|
echo "Hello $LOGNAME, Have nice computing"
|
|
return
|
|
}
|
|
To execute this SayHello() function just type it name as follows:
|
|
$ SayHello |