Skip to main content

Linux basic basch script if-then-else statement


If-then-else statement is quite a helpful statement and definitely helps to make life easier in scripting and other programming languages.

In basch script, the syntax is quite easy to follow and of course the logic is always the same even in other programming languages.

Logic can be followed literally as it is written.

Bash script below assumes that there 4 USB hard drive and is labelled as “USB Week1 Backup”, 
“USB Week2 Backup”, “USB Week3 Backup” and “USB Week4 Backup”.

If  the USB inserted and is mounted on “/media” the script gets the USB name and assigns it to variable name “PathBackup”

In Bash script the if statement is enclosed with open and close brackets, then spaces in between the brackets should be followed or else the script will result to an error.

if [ -d "$W1" ] – this statement checks if the ”-d” directory $W1  is present and assigns the path "/media/USB Week1 Backup" to PathBackup.

Spaces between the if statement , in open and close statement brackets should be followed.

In getting the value assigned to a variable use the dollar sign like “$W1”, in this case theW1 has the string value of ="/media/USB Week1 Backup".

  elif  - is else if (should be written in small letters)

  fi – to end or finish the if-then-else statement

rsync  -av /home/mybackup_data | gzip > "$PathBackup"`date '+%m-%d-%Y'`.zip

Statement above copies the files or data from /home/mybackup_data, and zip the files and filename is the date that it was copied.

Bash script below can be used as a backup utility use it on crontab to automate the backup.
-------------------------------------------------------------- 
   #!/bin/sh
  
   W1="/media/USB Week1 Backup"
   W2="/media/USB Week2 Backup"
   W3="/media/USB Week3 Backup"
   W4="/media/USB Week4 Backup"

         if [ -d "$W1" ]
                 then
                     PathBackup="$W1"

            elif [ -d "$W2" ]
                then
                     PathBackup="$W2"

            elif [ -d "$W3" ]
                 then
                     PathBackup="$W3"

            elif [ -d "$W4" ]
                 then
                      PathBackup="$W4"

          fi



rsync  -av /home/mybackup_data | gzip > "$PathBackup"`date '+%m-%d-%Y'`.zip

#-------------------------------------------------------------- 

As your mileage vary through the years of course, things will get exciting always. But if you are just beginning to grasp the world of bash scripting then start the basic right and understand it thoroughly, then the next will be easy.

Cheers! Hope it helps...Enjoy scripting..

=================
 
Catholic Rosary Guide  for Android:
Pray the Rosary every day, countless blessings will be showered upon your life if you recite the Rosary faithfully. 
https://play.google.com/store/apps/details?id=com.myrosaryapp

http://quickbytesstuff.blogspot.sg/2014/09/how-to-recite-rosary.html

Divine Mercy Chaplet Guide (A Powerful prayer) BFF = Be Filled Faith:

 

Comments

Popular posts from this blog

WMIC get computer name

WMIC get computer model, manufacturer, computer name and  username. WMIC is a command-line tool and that can generate information about computer model, its manufacturer, its username and other informations depending on the parameters provided. Why would you need a command line tool if there’s a GUI to check? If you have 20 or 100 computers, or even more. It’s quite a big task just checking the GUI to check the computer model and username. If you have remote computers, you need to delegate someone in the remote office or location to check. Or you can just write a batch file or script to automate the task. Here’s the code below on how get computer model, manufacturer and the username. Open an elevated command prompt and type:     wmic computersystem get "Model","Manufacturer", "Name", "UserName" Just copy and paste the code above, the word “computersystem” does not need to be change to a computer name. A

Notepad++ convert multiple lines to a single line and vice versa

Notepad++ is an awesome text editing tool, it can accept regex to process the text data. If the data is in a “.csv” format or comma separated values which is basically just a text file that can either be opened using a text editor, excel or even word. Notepad++ can process the contents of the file using regex. Example if the data has multiple rows or lines, and what is needed is to convert the whole lines of data into a single line. Notepad++ can easily do it using regex. However, if the data is on a single line and it needs to be converted into multiple lines or rows then regex can also be used for this case. Here’s an example on how to convert multiple rows or lines into a single line. Example data: Multiple rows, just a sample data. Press Ctrl+H, and  on "Find what" type: [\r\n]+ and on "Replace with" type with: , (white space) --white space is needed if need to have a space in between the data. See image below, "Regular Expression" must be se

Print error 016-799 - Fuji Film Xerox

016-799 Fuji Xerox or Fuji Film print error code. That shows a description error as “Print instruction Fail detected in decomposer.” The error code and error description are alien languages for users and even system administrators who are not familiar with Fuji Xerox error code. The error code is quite simple and easy to fix, if the job print goes to the printer but print out doesn’t come out. So, basically the print job was received by the printer, but the printer just doesn’t know what type of paper or what size to use or which tray to utilize for the print out. In some instances, this is just a paper mismatch but the error description; if using Windows 10 to print does not exactly points to what is the issue. First thing to check, is the paper size selected by the user to print. Example, if the printer configuration is A3 and A4 sizes only. But then the person printing the file accidentally chooses “A4 Cover” then this error 016-799 will occur.