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Run bash command from awk system only once
2019 Community Moderator ElectionMake awk use bash with the system() commandrecursive search for a pattern, then for each match print out the specific SEQUENCE: line number, file name, and no file contentsRun unix command on awk fieldWhat is wrong with my init.d script [Segmentation fault]Merging 2 files records by templateOverwrite file using AWK in a for loopTail Grep - Print surrounding lines until pattern is matchedBash Script to take a file as input and run awk command on another fileHow to run bash commands from within awk?Have `xargs` run the arguments it's received every <maximum amount of time> instead of every `-n` arguments?
I am using tail -F to monitor a severe weather alert server log file and awk to filter and execute a command if the conditions for an alert are met. I need to execute the bash command(an ssh command sent to a Pi to trigger an alert LED) in system only once, not one time for every match. Everything is working except the system command is running once for every line matched. Here is what I have so far:
tail -F /home/user/test.txt | stdbuf -oL awk '/ZZZ029/getline; if (/SV.W/) print system("command")'
Current output(number of lines could vary):
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Expected output:
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
I need just one line of output so the system command will run only once. Or just a way to run the command once regardless of number of lines of output.
shell-script awk
asked yesterday
JakeJake
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
|
show 2 more comments
I am using tail -F to monitor a severe weather alert server log file and awk to filter and execute a command if the conditions for an alert are met. I need to execute the bash command(an ssh command sent to a Pi to trigger an alert LED) in system only once, not one time for every match. Everything is working except the system command is running once for every line matched. Here is what I have so far:
tail -F /home/user/test.txt | stdbuf -oL awk '/ZZZ029/getline; if (/SV.W/) print system("command")'
Current output(number of lines could vary):
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Expected output:
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
I need just one line of output so the system command will run only once. Or just a way to run the command once regardless of number of lines of output.
shell-script awk
asked yesterday
JakeJake
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
2
after you calllsystem("command")you want the whole pipeline to stop, or you want the pipeline to continue but for awk to never callsystemagain?
– Jeff Schaller
yesterday
Note thatsystem()runsshto interpret thecommandnotbash. If you want to startbashto interpret bash specific code, you'll need to constructshcode that runsbash -c bash-specific-code-herewhere that bash-specific code will have to be quoted as per sh rules.
– Stéphane Chazelas
yesterday
@JeffSchaller I want the tail -F to continue watching the file but to run the system() command only once for each time matches are found, regardless of how many matches there are.
– Jake
9 hours ago
I'm having trouble putting together these two phrases: "run the system() command once" -- and -- "each time matches are found, regardless of how many matches there are". Do you want the command run for the first match, and that first match only?
– Jeff Schaller
9 hours ago
Yes, for the first match only.
– Jake
9 hours ago
|
show 2 more comments
I am using tail -F to monitor a severe weather alert server log file and awk to filter and execute a command if the conditions for an alert are met. I need to execute the bash command(an ssh command sent to a Pi to trigger an alert LED) in system only once, not one time for every match. Everything is working except the system command is running once for every line matched. Here is what I have so far:
tail -F /home/user/test.txt | stdbuf -oL awk '/ZZZ029/getline; if (/SV.W/) print system("command")'
Current output(number of lines could vary):
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Expected output:
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
I need just one line of output so the system command will run only once. Or just a way to run the command once regardless of number of lines of output.
shell-script awk
asked yesterday
JakeJake
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I am using tail -F to monitor a severe weather alert server log file and awk to filter and execute a command if the conditions for an alert are met. I need to execute the bash command(an ssh command sent to a Pi to trigger an alert LED) in system only once, not one time for every match. Everything is working except the system command is running once for every line matched. Here is what I have so far:
tail -F /home/user/test.txt | stdbuf -oL awk '/ZZZ029/getline; if (/SV.W/) print system("command")'
Current output(number of lines could vary):
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Expected output:
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
I need just one line of output so the system command will run only once. Or just a way to run the command once regardless of number of lines of output.
shell-script awk
shell-script awk
asked yesterday
JakeJake
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked yesterday
JakeJake
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 7 hours ago
Jake
asked yesterday
JakeJake
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked yesterday
JakeJake
11
asked yesterday
JakeJake
11
11
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Jake is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
2
after you calllsystem("command")you want the whole pipeline to stop, or you want the pipeline to continue but for awk to never callsystemagain?
– Jeff Schaller
yesterday
Note thatsystem()runsshto interpret thecommandnotbash. If you want to startbashto interpret bash specific code, you'll need to constructshcode that runsbash -c bash-specific-code-herewhere that bash-specific code will have to be quoted as per sh rules.
– Stéphane Chazelas
yesterday
@JeffSchaller I want the tail -F to continue watching the file but to run the system() command only once for each time matches are found, regardless of how many matches there are.
– Jake
9 hours ago
I'm having trouble putting together these two phrases: "run the system() command once" -- and -- "each time matches are found, regardless of how many matches there are". Do you want the command run for the first match, and that first match only?
– Jeff Schaller
9 hours ago
Yes, for the first match only.
– Jake
9 hours ago
|
show 2 more comments
2
after you calllsystem("command")you want the whole pipeline to stop, or you want the pipeline to continue but for awk to never callsystemagain?
– Jeff Schaller
yesterday
Note thatsystem()runsshto interpret thecommandnotbash. If you want to startbashto interpret bash specific code, you'll need to constructshcode that runsbash -c bash-specific-code-herewhere that bash-specific code will have to be quoted as per sh rules.
– Stéphane Chazelas
yesterday
@JeffSchaller I want the tail -F to continue watching the file but to run the system() command only once for each time matches are found, regardless of how many matches there are.
– Jake
9 hours ago
I'm having trouble putting together these two phrases: "run the system() command once" -- and -- "each time matches are found, regardless of how many matches there are". Do you want the command run for the first match, and that first match only?
– Jeff Schaller
9 hours ago
Yes, for the first match only.
– Jake
9 hours ago
2
2
after you calll
system("command") you want the whole pipeline to stop, or you want the pipeline to continue but for awk to never call system again?– Jeff Schaller
yesterday
after you calll
system("command") you want the whole pipeline to stop, or you want the pipeline to continue but for awk to never call system again?– Jeff Schaller
yesterday
Note that
system() runs sh to interpret the command not bash. If you want to start bash to interpret bash specific code, you'll need to construct sh code that runs bash -c bash-specific-code-here where that bash-specific code will have to be quoted as per sh rules.– Stéphane Chazelas
yesterday
Note that
system() runs sh to interpret the command not bash. If you want to start bash to interpret bash specific code, you'll need to construct sh code that runs bash -c bash-specific-code-here where that bash-specific code will have to be quoted as per sh rules.– Stéphane Chazelas
yesterday
@JeffSchaller I want the tail -F to continue watching the file but to run the system() command only once for each time matches are found, regardless of how many matches there are.
– Jake
9 hours ago
@JeffSchaller I want the tail -F to continue watching the file but to run the system() command only once for each time matches are found, regardless of how many matches there are.
– Jake
9 hours ago
I'm having trouble putting together these two phrases: "run the system() command once" -- and -- "each time matches are found, regardless of how many matches there are". Do you want the command run for the first match, and that first match only?
– Jeff Schaller
9 hours ago
I'm having trouble putting together these two phrases: "run the system() command once" -- and -- "each time matches are found, regardless of how many matches there are". Do you want the command run for the first match, and that first match only?
– Jeff Schaller
9 hours ago
Yes, for the first match only.
– Jake
9 hours ago
Yes, for the first match only.
– Jake
9 hours ago
|
show 2 more comments
1 Answer
1
active
oldest
votes
From current output what you provided from my understanding you want to remove duplicates
pipeline_previous_command|awk 'if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Suppose if you want ouput as output which mentioned above
raveen:~$ pipeline_previous_command | awk '/W.0028/if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after thegetline; if (/SV.W/)command?
– Jake
7 hours ago
add a comment |
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1 Answer
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1 Answer
1
active
oldest
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active
oldest
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active
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votes
From current output what you provided from my understanding you want to remove duplicates
pipeline_previous_command|awk 'if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Suppose if you want ouput as output which mentioned above
raveen:~$ pipeline_previous_command | awk '/W.0028/if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after thegetline; if (/SV.W/)command?
– Jake
7 hours ago
add a comment |
From current output what you provided from my understanding you want to remove duplicates
pipeline_previous_command|awk 'if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Suppose if you want ouput as output which mentioned above
raveen:~$ pipeline_previous_command | awk '/W.0028/if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after thegetline; if (/SV.W/)command?
– Jake
7 hours ago
add a comment |
From current output what you provided from my understanding you want to remove duplicates
pipeline_previous_command|awk 'if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Suppose if you want ouput as output which mentioned above
raveen:~$ pipeline_previous_command | awk '/W.0028/if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
From current output what you provided from my understanding you want to remove duplicates
pipeline_previous_command|awk 'if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
/O.CON.KFFC.SV.W.0021.000000T0000Z-190315T0015Z/
Suppose if you want ouput as output which mentioned above
raveen:~$ pipeline_previous_command | awk '/W.0028/if(!seen[$1]++)print $1'
/O.NEW.KBMX.SV.W.0028.190314T2350Z-190315T0030Z/
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
answered 7 hours ago
Praveen Kumar BSPraveen Kumar BS
1,6471311
1,6471311
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after thegetline; if (/SV.W/)command?
– Jake
7 hours ago
add a comment |
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after thegetline; if (/SV.W/)command?
– Jake
7 hours ago
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after the
getline; if (/SV.W/) command?– Jake
7 hours ago
Yes, remove duplicates of SV.W match. I'm not understanding how to work this into my current script, however. Does it go after the
getline; if (/SV.W/) command?– Jake
7 hours ago
add a comment |
Jake is a new contributor. Be nice, and check out our Code of Conduct.
Jake is a new contributor. Be nice, and check out our Code of Conduct.
Jake is a new contributor. Be nice, and check out our Code of Conduct.
Jake is a new contributor. Be nice, and check out our Code of Conduct.
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2
after you calll
system("command")you want the whole pipeline to stop, or you want the pipeline to continue but for awk to never callsystemagain?– Jeff Schaller
yesterday
Note that
system()runsshto interpret thecommandnotbash. If you want to startbashto interpret bash specific code, you'll need to constructshcode that runsbash -c bash-specific-code-herewhere that bash-specific code will have to be quoted as per sh rules.– Stéphane Chazelas
yesterday
@JeffSchaller I want the tail -F to continue watching the file but to run the system() command only once for each time matches are found, regardless of how many matches there are.
– Jake
9 hours ago
I'm having trouble putting together these two phrases: "run the system() command once" -- and -- "each time matches are found, regardless of how many matches there are". Do you want the command run for the first match, and that first match only?
– Jeff Schaller
9 hours ago
Yes, for the first match only.
– Jake
9 hours ago