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How can I continuously run a bash script checking if a value has changed?

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1

1

I have a PHP script getAnalytics.php that when called, returns a specific integer value. I want to be able to call getAnalytics.php in a bash script that runs continuously checking the PHP script every 30 seconds to see if the value returned has changed.

How would I go about doing this? Or would you recommend a different method?

bash

share|improve this question

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

bumped to the homepage by Community♦ 18 mins ago

This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

add a comment | 

1

1

I have a PHP script getAnalytics.php that when called, returns a specific integer value. I want to be able to call getAnalytics.php in a bash script that runs continuously checking the PHP script every 30 seconds to see if the value returned has changed.

How would I go about doing this? Or would you recommend a different method?

bash

share|improve this question

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

bumped to the homepage by Community♦ 18 mins ago

This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

add a comment | 

I have a PHP script getAnalytics.php that when called, returns a specific integer value. I want to be able to call getAnalytics.php in a bash script that runs continuously checking the PHP script every 30 seconds to see if the value returned has changed.

How would I go about doing this? Or would you recommend a different method?

bash

share|improve this question

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

share|improve this question

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

share|improve this question

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

edited Dec 14 '14 at 16:40

Anthon

62.1k17109172

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

asked Dec 14 '14 at 16:38

Trey CopelandTrey Copeland

1062

2 Answers
2

active

oldest

votes

0

If you could relax your requirements to a minute between runs, you can easily do this via a cron entry. The advantage of this process is that a program does not simply sit around (and possibly die) causing you to miss some data or window. Also no special steps would be required to start it up between reboots.

share|improve this answer

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

add a comment | 

0

If you have no better indication (watching some log file e.g.) to get notification of a possible change just endlessly loop in bash:

res=

while [ 1 ] ; do

   old_result=$res

   res=$(/path/to/getAnalytics.php)

   echo "result: $res"

   if [ "$old_result" != "$res" ]; then

     echo "result has changed"

   fi

   sleep 30

done

You will need Ctrl+C to exit. If you want to exit on a particular value (e.g. 42) printed by the script set res to some dummy value at the beginning and then test for [ "$res" != "42" ]

share|improve this answer

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I keep getting /myapp/test.php: line 1: 345234: command not found result,
  
  – Trey Copeland
  Dec 14 '14 at 16:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @TreyCopeland what happens when you run /myapp/test.php from the commandline? Does that file have a shebang line? If not it is not an executable script and you have to call it with php /myapp/test.php.
  
  – Anthon
  Dec 14 '14 at 17:21
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Why while [ 1 ] ; rather than while :; or while true; ?
  
  – PM 2Ring
  Dec 15 '14 at 6:55
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @PM2Ring Looks better after 30 years of usage?
  
  – Anthon
  Dec 15 '14 at 7:08
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @PM2Ring I don't think that speed is an issue if the OP can use PHP. And this way, where to put the exit loop with testing on $res requires less explaining.
  
  – Anthon
  Dec 15 '14 at 7:21
  

  
  
  
  

 | 
show 1 more comment

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0

If you could relax your requirements to a minute between runs, you can easily do this via a cron entry. The advantage of this process is that a program does not simply sit around (and possibly die) causing you to miss some data or window. Also no special steps would be required to start it up between reboots.

share|improve this answer

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

add a comment | 

0

If you could relax your requirements to a minute between runs, you can easily do this via a cron entry. The advantage of this process is that a program does not simply sit around (and possibly die) causing you to miss some data or window. Also no special steps would be required to start it up between reboots.

share|improve this answer

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

add a comment | 

If you could relax your requirements to a minute between runs, you can easily do this via a cron entry. The advantage of this process is that a program does not simply sit around (and possibly die) causing you to miss some data or window. Also no special steps would be required to start it up between reboots.

share|improve this answer

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

share|improve this answer

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

answered Dec 14 '14 at 19:43

mdpcmdpc

5,09621838

0

If you have no better indication (watching some log file e.g.) to get notification of a possible change just endlessly loop in bash:

res=

while [ 1 ] ; do

   old_result=$res

   res=$(/path/to/getAnalytics.php)

   echo "result: $res"

   if [ "$old_result" != "$res" ]; then

     echo "result has changed"

   fi

   sleep 30

done

You will need Ctrl+C to exit. If you want to exit on a particular value (e.g. 42) printed by the script set res to some dummy value at the beginning and then test for [ "$res" != "42" ]

share|improve this answer

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I keep getting /myapp/test.php: line 1: 345234: command not found result,
  
  – Trey Copeland
  Dec 14 '14 at 16:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @TreyCopeland what happens when you run /myapp/test.php from the commandline? Does that file have a shebang line? If not it is not an executable script and you have to call it with php /myapp/test.php.
  
  – Anthon
  Dec 14 '14 at 17:21
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Why while [ 1 ] ; rather than while :; or while true; ?
  
  – PM 2Ring
  Dec 15 '14 at 6:55
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @PM2Ring Looks better after 30 years of usage?
  
  – Anthon
  Dec 15 '14 at 7:08
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @PM2Ring I don't think that speed is an issue if the OP can use PHP. And this way, where to put the exit loop with testing on $res requires less explaining.
  
  – Anthon
  Dec 15 '14 at 7:21
  

  
  
  
  

 | 
show 1 more comment

0

If you have no better indication (watching some log file e.g.) to get notification of a possible change just endlessly loop in bash:

res=

while [ 1 ] ; do

   old_result=$res

   res=$(/path/to/getAnalytics.php)

   echo "result: $res"

   if [ "$old_result" != "$res" ]; then

     echo "result has changed"

   fi

   sleep 30

done

You will need Ctrl+C to exit. If you want to exit on a particular value (e.g. 42) printed by the script set res to some dummy value at the beginning and then test for [ "$res" != "42" ]

share|improve this answer

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I keep getting /myapp/test.php: line 1: 345234: command not found result,
  
  – Trey Copeland
  Dec 14 '14 at 16:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @TreyCopeland what happens when you run /myapp/test.php from the commandline? Does that file have a shebang line? If not it is not an executable script and you have to call it with php /myapp/test.php.
  
  – Anthon
  Dec 14 '14 at 17:21
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Why while [ 1 ] ; rather than while :; or while true; ?
  
  – PM 2Ring
  Dec 15 '14 at 6:55
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @PM2Ring Looks better after 30 years of usage?
  
  – Anthon
  Dec 15 '14 at 7:08
  
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  @PM2Ring I don't think that speed is an issue if the OP can use PHP. And this way, where to put the exit loop with testing on $res requires less explaining.
  
  – Anthon
  Dec 15 '14 at 7:21
  

  
  
  
  

 | 
show 1 more comment

If you have no better indication (watching some log file e.g.) to get notification of a possible change just endlessly loop in bash:

res=

while [ 1 ] ; do

   old_result=$res

   res=$(/path/to/getAnalytics.php)

   echo "result: $res"

   if [ "$old_result" != "$res" ]; then

     echo "result has changed"

   fi

   sleep 30

done

You will need Ctrl+C to exit. If you want to exit on a particular value (e.g. 42) printed by the script set res to some dummy value at the beginning and then test for [ "$res" != "42" ]

share|improve this answer

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172

res=

while [ 1 ] ; do

   old_result=$res

   res=$(/path/to/getAnalytics.php)

   echo "result: $res"

   if [ "$old_result" != "$res" ]; then

     echo "result has changed"

   fi

   sleep 30

done

share|improve this answer

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

edited Dec 14 '14 at 21:28

Gilles

552k13211291637

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172

answered Dec 14 '14 at 16:43

AnthonAnthon

62.1k17109172