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Old 10-25-2011, 01:12 PM   #1
huntaz556
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Read a text file with bash


Im making a bash script and i need to check a text file to see if what someone entered is already there , if it is already there then i want the script to say you have already entered this are you sure? but im not sure how to do that can you help me please ,

thank you!
 
Old 10-25-2011, 01:22 PM   #2
TobiSGD
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You can use the grep command for that. For example
Code:
grep -q $USERINPUT textfile
This will search for the text in the variable $USERINPUT in the file textfile without printing the found matches (if any, option -q). grep will return an exit code of 0 if the text is found, otherwise it will return exit code 1.

For more info on grep use
Code:
man grep

Last edited by TobiSGD; 10-25-2011 at 01:23 PM.
 
Old 10-25-2011, 01:36 PM   #3
huntaz556
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Quote:
Originally Posted by TobiSGD View Post
You can use the grep command for that. For example
Code:
grep -q $USERINPUT textfile
This will search for the text in the variable $USERINPUT in the file textfile without printing the found matches (if any, option -q). grep will return an exit code of 0 if the text is found, otherwise it will return exit code 1.

For more info on grep use
Code:
man grep
thank you that works for searching the file but how do i implement this into my code and it will be between an if and elif statement thanks !
 
Old 10-26-2011, 03:49 AM   #4
grail
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Try putting it in your if statement ... you will be pleasantly surprised
 
Old 10-27-2011, 06:02 AM   #5
AnanthaP
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Further note that in your future bash script, $? will return contain the return value of the last executed command.

OK
 
Old 10-27-2011, 07:02 AM   #6
grail
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Quote:
Further note that in your future bash script, $? will return contain the return value of the last executed command.
But not required if you follow my advice
 
  


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