How can use tail for notifications above 0.99% loadav?

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#!/bin/bash

( tail -f -n0 /proc/loadavg 2> /dev/null & ) | grep -q "^[1-9]"
echo 'The millenium crystals are gunna blow!'

I though I was being clever and that would work. It just hangs and never reacts unless from run start and the first char is [1-9]

edited Mar 7 at 9:22

Inian

5,3751531

asked Mar 7 at 9:20

Stuart Naylor

Just to nitpick: The load averages aren't percentages.

– Kusalananda♦
Mar 7 at 9:54

add a comment |

#!/bin/bash

( tail -f -n0 /proc/loadavg 2> /dev/null & ) | grep -q "^[1-9]"
echo 'The millenium crystals are gunna blow!'

I though I was being clever and that would work. It just hangs and never reacts unless from run start and the first char is [1-9]

edited Mar 7 at 9:22

Inian

5,3751531

asked Mar 7 at 9:20

Stuart Naylor

Just to nitpick: The load averages aren't percentages.

– Kusalananda♦
Mar 7 at 9:54

add a comment |

#!/bin/bash

( tail -f -n0 /proc/loadavg 2> /dev/null & ) | grep -q "^[1-9]"
echo 'The millenium crystals are gunna blow!'

I though I was being clever and that would work. It just hangs and never reacts unless from run start and the first char is [1-9]

edited Mar 7 at 9:22

Inian

5,3751531

asked Mar 7 at 9:20

Stuart Naylor

#!/bin/bash

( tail -f -n0 /proc/loadavg 2> /dev/null & ) | grep -q "^[1-9]"
echo 'The millenium crystals are gunna blow!'

I though I was being clever and that would work. It just hangs and never reacts unless from run start and the first char is [1-9]

tail

edited Mar 7 at 9:22

Inian

5,3751531

asked Mar 7 at 9:20

Stuart Naylor

edited Mar 7 at 9:22

Inian

5,3751531

asked Mar 7 at 9:20

Stuart Naylor

edited Mar 7 at 9:22

Inian

5,3751531

edited Mar 7 at 9:22

Inian

5,3751531

edited Mar 7 at 9:22

Inian

5,3751531

asked Mar 7 at 9:20

Stuart Naylor

asked Mar 7 at 9:20

Stuart Naylor

asked Mar 7 at 9:20

Stuart Naylor

Just to nitpick: The load averages aren't percentages.

– Kusalananda♦
Mar 7 at 9:54

add a comment |

Just to nitpick: The load averages aren't percentages.

– Kusalananda♦
Mar 7 at 9:54

Just to nitpick: The load averages aren't percentages.

– Kusalananda♦
Mar 7 at 9:54

add a comment |

2 Answers
2

active

oldest

votes

tail does look for new lines, not for line chages:

-f, --follow[=descriptor]
 output appended data as the file grows;

If you want to verify this behaviour for yourself, you can use this command to change a line in testfile:

while true ; do
 sed "s/^.*$/$(date)/" -i testfile
 sleep 1
done

You could use a wile loop to check for line changes:

while true ; do
 grep -q "^[1-9]" /proc/loadavg && echo "$message"
 sleep 1
done

answered Mar 7 at 9:51

ctx

1,749515

add a comment |

I think you can in conjunction use tail with grep for changes and not just new lines.

I just read before I came here that /proc/loadavg isn't actually a file but a kernel interface and maybe you are right, but even if it could I will still be up the swanny.

I was hoping for an inotify notification rather than the load of just constant loops but seems like computer says no.

answered Mar 7 at 10:01

Stuart Naylor

I take it that something like Nagios is not on the table for this?

– Raman Sailopal
Mar 7 at 10:58

:) maybe not as nagios is likely doing the same and polling rather than using a tail inotify Just means I can not use tail in a notification event scheme and will just have to use polling like ctx suggests

– Stuart Naylor
Mar 8 at 2:48

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

tail does look for new lines, not for line chages:

-f, --follow[=descriptor]
 output appended data as the file grows;

If you want to verify this behaviour for yourself, you can use this command to change a line in testfile:

while true ; do
 sed "s/^.*$/$(date)/" -i testfile
 sleep 1
done

You could use a wile loop to check for line changes:

while true ; do
 grep -q "^[1-9]" /proc/loadavg && echo "$message"
 sleep 1
done

answered Mar 7 at 9:51

ctx

1,749515

add a comment |

tail does look for new lines, not for line chages:

-f, --follow[=descriptor]
 output appended data as the file grows;

If you want to verify this behaviour for yourself, you can use this command to change a line in testfile:

while true ; do
 sed "s/^.*$/$(date)/" -i testfile
 sleep 1
done

You could use a wile loop to check for line changes:

while true ; do
 grep -q "^[1-9]" /proc/loadavg && echo "$message"
 sleep 1
done

answered Mar 7 at 9:51

ctx

1,749515

add a comment |

tail does look for new lines, not for line chages:

-f, --follow[=descriptor]
 output appended data as the file grows;

If you want to verify this behaviour for yourself, you can use this command to change a line in testfile:

while true ; do
 sed "s/^.*$/$(date)/" -i testfile
 sleep 1
done

You could use a wile loop to check for line changes:

while true ; do
 grep -q "^[1-9]" /proc/loadavg && echo "$message"
 sleep 1
done

answered Mar 7 at 9:51

ctx

1,749515

tail does look for new lines, not for line chages:

-f, --follow[=descriptor]
 output appended data as the file grows;

If you want to verify this behaviour for yourself, you can use this command to change a line in testfile:

while true ; do
 sed "s/^.*$/$(date)/" -i testfile
 sleep 1
done

You could use a wile loop to check for line changes:

while true ; do
 grep -q "^[1-9]" /proc/loadavg && echo "$message"
 sleep 1
done

answered Mar 7 at 9:51

ctx

1,749515

answered Mar 7 at 9:51

ctx

1,749515

answered Mar 7 at 9:51

ctx

1,749515

answered Mar 7 at 9:51

ctx

1,749515

add a comment |

I think you can in conjunction use tail with grep for changes and not just new lines.

I just read before I came here that /proc/loadavg isn't actually a file but a kernel interface and maybe you are right, but even if it could I will still be up the swanny.

I was hoping for an inotify notification rather than the load of just constant loops but seems like computer says no.

answered Mar 7 at 10:01

Stuart Naylor

I take it that something like Nagios is not on the table for this?

– Raman Sailopal
Mar 7 at 10:58

:) maybe not as nagios is likely doing the same and polling rather than using a tail inotify Just means I can not use tail in a notification event scheme and will just have to use polling like ctx suggests

– Stuart Naylor
Mar 8 at 2:48

add a comment |

I think you can in conjunction use tail with grep for changes and not just new lines.

I just read before I came here that /proc/loadavg isn't actually a file but a kernel interface and maybe you are right, but even if it could I will still be up the swanny.

I was hoping for an inotify notification rather than the load of just constant loops but seems like computer says no.

answered Mar 7 at 10:01

Stuart Naylor

I take it that something like Nagios is not on the table for this?

– Raman Sailopal
Mar 7 at 10:58

:) maybe not as nagios is likely doing the same and polling rather than using a tail inotify Just means I can not use tail in a notification event scheme and will just have to use polling like ctx suggests

– Stuart Naylor
Mar 8 at 2:48

add a comment |

I think you can in conjunction use tail with grep for changes and not just new lines.

I just read before I came here that /proc/loadavg isn't actually a file but a kernel interface and maybe you are right, but even if it could I will still be up the swanny.

I was hoping for an inotify notification rather than the load of just constant loops but seems like computer says no.

answered Mar 7 at 10:01

Stuart Naylor

I think you can in conjunction use tail with grep for changes and not just new lines.

I just read before I came here that /proc/loadavg isn't actually a file but a kernel interface and maybe you are right, but even if it could I will still be up the swanny.

I was hoping for an inotify notification rather than the load of just constant loops but seems like computer says no.

answered Mar 7 at 10:01

Stuart Naylor

answered Mar 7 at 10:01

Stuart Naylor

answered Mar 7 at 10:01

Stuart Naylor

answered Mar 7 at 10:01

Stuart Naylor

I take it that something like Nagios is not on the table for this?

– Raman Sailopal
Mar 7 at 10:58

:) maybe not as nagios is likely doing the same and polling rather than using a tail inotify Just means I can not use tail in a notification event scheme and will just have to use polling like ctx suggests

– Stuart Naylor
Mar 8 at 2:48

add a comment |

I take it that something like Nagios is not on the table for this?

– Raman Sailopal
Mar 7 at 10:58

:) maybe not as nagios is likely doing the same and polling rather than using a tail inotify Just means I can not use tail in a notification event scheme and will just have to use polling like ctx suggests

– Stuart Naylor
Mar 8 at 2:48

I take it that something like Nagios is not on the table for this?

– Raman Sailopal
Mar 7 at 10:58

:) maybe not as nagios is likely doing the same and polling rather than using a tail inotify Just means I can not use tail in a notification event scheme and will just have to use polling like ctx suggests

– Stuart Naylor
Mar 8 at 2:48

add a comment |

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