Error while using 'if' with the count in Bash [on hold]

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up vote
3
down vote

favorite












What's wrong with the following? I get a [: too many arguments error.



if [ 'wc -l pid.txt | awk 'print $1'' -ge "1" ]
then
 for line in $(cat pid.txt)
 do
 kill $line
 done
else
 rm pid.txt
fi



bash shell-script shell




share|improve this question













put on hold as off-topic by ilkkachu, Rui F Ribeiro, slm♦ Aug 4 at 0:45


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "Questions describing a problem that can't be reproduced and seemingly went away on its own (or went away when a typo was fixed) are off-topic as they are unlikely to help future readers." – ilkkachu, Rui F Ribeiro, slm
If this question can be reworded to fit the rules in the help center, please edit the question.








  • 1




    The single quotes around your command should be back-ticks. Is that a typo in your post or are you using the wrong symbol?
    – Andy Dalton
    Aug 3 at 20:30










  • oops I feel dumb. I am using single quotes and thats the problem. Thanks a lot.
    – Vas
    Aug 3 at 20:36






  • 1




    @Vas Your "problem" was the single quotes, but there's a lot more that could be improved.
    – Kusalananda
    Aug 3 at 20:58
















up vote
3
down vote

favorite












What's wrong with the following? I get a [: too many arguments error.



if [ 'wc -l pid.txt | awk 'print $1'' -ge "1" ]
then
 for line in $(cat pid.txt)
 do
 kill $line
 done
else
 rm pid.txt
fi



bash shell-script shell




share|improve this question













put on hold as off-topic by ilkkachu, Rui F Ribeiro, slm♦ Aug 4 at 0:45


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "Questions describing a problem that can't be reproduced and seemingly went away on its own (or went away when a typo was fixed) are off-topic as they are unlikely to help future readers." – ilkkachu, Rui F Ribeiro, slm
If this question can be reworded to fit the rules in the help center, please edit the question.








  • 1




    The single quotes around your command should be back-ticks. Is that a typo in your post or are you using the wrong symbol?
    – Andy Dalton
    Aug 3 at 20:30










  • oops I feel dumb. I am using single quotes and thats the problem. Thanks a lot.
    – Vas
    Aug 3 at 20:36






  • 1




    @Vas Your "problem" was the single quotes, but there's a lot more that could be improved.
    – Kusalananda
    Aug 3 at 20:58












up vote
3
down vote

favorite









up vote
3
down vote

favorite











What's wrong with the following? I get a [: too many arguments error.



if [ 'wc -l pid.txt | awk 'print $1'' -ge "1" ]
then
 for line in $(cat pid.txt)
 do
 kill $line
 done
else
 rm pid.txt
fi



bash shell-script shell




share|improve this question













What's wrong with the following? I get a [: too many arguments error.



if [ 'wc -l pid.txt | awk 'print $1'' -ge "1" ]
then
 for line in $(cat pid.txt)
 do
 kill $line
 done
else
 rm pid.txt
fi




bash shell-script shell





share|improve this question












share|improve this question




share|improve this question








edited Aug 4 at 0:40









Peter Mortensen

76348




76348









asked Aug 3 at 20:19









Vas

203




203




put on hold as off-topic by ilkkachu, Rui F Ribeiro, slm♦ Aug 4 at 0:45


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "Questions describing a problem that can't be reproduced and seemingly went away on its own (or went away when a typo was fixed) are off-topic as they are unlikely to help future readers." – ilkkachu, Rui F Ribeiro, slm
If this question can be reworded to fit the rules in the help center, please edit the question.




put on hold as off-topic by ilkkachu, Rui F Ribeiro, slm♦ Aug 4 at 0:45


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "Questions describing a problem that can't be reproduced and seemingly went away on its own (or went away when a typo was fixed) are off-topic as they are unlikely to help future readers." – ilkkachu, Rui F Ribeiro, slm
If this question can be reworded to fit the rules in the help center, please edit the question.







  • 1




    The single quotes around your command should be back-ticks. Is that a typo in your post or are you using the wrong symbol?
    – Andy Dalton
    Aug 3 at 20:30










  • oops I feel dumb. I am using single quotes and thats the problem. Thanks a lot.
    – Vas
    Aug 3 at 20:36






  • 1




    @Vas Your "problem" was the single quotes, but there's a lot more that could be improved.
    – Kusalananda
    Aug 3 at 20:58












  • 1




    The single quotes around your command should be back-ticks. Is that a typo in your post or are you using the wrong symbol?
    – Andy Dalton
    Aug 3 at 20:30










  • oops I feel dumb. I am using single quotes and thats the problem. Thanks a lot.
    – Vas
    Aug 3 at 20:36






  • 1




    @Vas Your "problem" was the single quotes, but there's a lot more that could be improved.
    – Kusalananda
    Aug 3 at 20:58







1




1




The single quotes around your command should be back-ticks. Is that a typo in your post or are you using the wrong symbol?
– Andy Dalton
Aug 3 at 20:30




The single quotes around your command should be back-ticks. Is that a typo in your post or are you using the wrong symbol?
– Andy Dalton
Aug 3 at 20:30












oops I feel dumb. I am using single quotes and thats the problem. Thanks a lot.
– Vas
Aug 3 at 20:36




oops I feel dumb. I am using single quotes and thats the problem. Thanks a lot.
– Vas
Aug 3 at 20:36




1




1




@Vas Your "problem" was the single quotes, but there's a lot more that could be improved.
– Kusalananda
Aug 3 at 20:58




@Vas Your "problem" was the single quotes, but there's a lot more that could be improved.
– Kusalananda
Aug 3 at 20:58










1 Answer
1






active

oldest

votes

















up vote
6
down vote













Improved further thanks to Kusalananda.



  • Testing for contents of the file is not necessary as the while read loop won't run on an empty file.

  • You could then simply use [ -s pid.txt ] || rm pid.txt to remove the pid file. However, do you really have a reason to keep the file after processing? It seems likely you would want to remove it regardless.

while read -r line
do
 kill "$line"
done < pid.txt
[ -s pid.txt ] || rm pid.txt


A while read loop is being used instead
of for $(cat ...). Don't read lines with for.



The -r option specifies "do not allow backslashes to escape any characters" which shouldn't really be an issue in a file of pids, but it is best practice to always set unless there is a specific reason not to.






share|improve this answer



















  • 3




    The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
    – Kusalananda
    Aug 3 at 20:52











  • One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
    – Kusalananda
    Aug 3 at 21:09






  • 1




    [ -s pid.txt ] || rm pid.txt to remove if empty, right?
    – ilkkachu
    Aug 3 at 23:48










  • Good catch @ilkkachu, thanks
    – Jesse_b
    Aug 3 at 23:55










  • @ilkkachu Sorry, got the test backwards... duh.
    – Kusalananda
    2 days ago

















1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
6
down vote













Improved further thanks to Kusalananda.



  • Testing for contents of the file is not necessary as the while read loop won't run on an empty file.

  • You could then simply use [ -s pid.txt ] || rm pid.txt to remove the pid file. However, do you really have a reason to keep the file after processing? It seems likely you would want to remove it regardless.

while read -r line
do
 kill "$line"
done < pid.txt
[ -s pid.txt ] || rm pid.txt


A while read loop is being used instead
of for $(cat ...). Don't read lines with for.



The -r option specifies "do not allow backslashes to escape any characters" which shouldn't really be an issue in a file of pids, but it is best practice to always set unless there is a specific reason not to.






share|improve this answer



















  • 3




    The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
    – Kusalananda
    Aug 3 at 20:52











  • One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
    – Kusalananda
    Aug 3 at 21:09






  • 1




    [ -s pid.txt ] || rm pid.txt to remove if empty, right?
    – ilkkachu
    Aug 3 at 23:48










  • Good catch @ilkkachu, thanks
    – Jesse_b
    Aug 3 at 23:55










  • @ilkkachu Sorry, got the test backwards... duh.
    – Kusalananda
    2 days ago














up vote
6
down vote













Improved further thanks to Kusalananda.



  • Testing for contents of the file is not necessary as the while read loop won't run on an empty file.

  • You could then simply use [ -s pid.txt ] || rm pid.txt to remove the pid file. However, do you really have a reason to keep the file after processing? It seems likely you would want to remove it regardless.

while read -r line
do
 kill "$line"
done < pid.txt
[ -s pid.txt ] || rm pid.txt


A while read loop is being used instead
of for $(cat ...). Don't read lines with for.



The -r option specifies "do not allow backslashes to escape any characters" which shouldn't really be an issue in a file of pids, but it is best practice to always set unless there is a specific reason not to.






share|improve this answer



















  • 3




    The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
    – Kusalananda
    Aug 3 at 20:52











  • One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
    – Kusalananda
    Aug 3 at 21:09






  • 1




    [ -s pid.txt ] || rm pid.txt to remove if empty, right?
    – ilkkachu
    Aug 3 at 23:48










  • Good catch @ilkkachu, thanks
    – Jesse_b
    Aug 3 at 23:55










  • @ilkkachu Sorry, got the test backwards... duh.
    – Kusalananda
    2 days ago












up vote
6
down vote










up vote
6
down vote









Improved further thanks to Kusalananda.



  • Testing for contents of the file is not necessary as the while read loop won't run on an empty file.

  • You could then simply use [ -s pid.txt ] || rm pid.txt to remove the pid file. However, do you really have a reason to keep the file after processing? It seems likely you would want to remove it regardless.

while read -r line
do
 kill "$line"
done < pid.txt
[ -s pid.txt ] || rm pid.txt


A while read loop is being used instead
of for $(cat ...). Don't read lines with for.



The -r option specifies "do not allow backslashes to escape any characters" which shouldn't really be an issue in a file of pids, but it is best practice to always set unless there is a specific reason not to.






share|improve this answer















Improved further thanks to Kusalananda.



  • Testing for contents of the file is not necessary as the while read loop won't run on an empty file.

  • You could then simply use [ -s pid.txt ] || rm pid.txt to remove the pid file. However, do you really have a reason to keep the file after processing? It seems likely you would want to remove it regardless.

while read -r line
do
 kill "$line"
done < pid.txt
[ -s pid.txt ] || rm pid.txt


A while read loop is being used instead
of for $(cat ...). Don't read lines with for.



The -r option specifies "do not allow backslashes to escape any characters" which shouldn't really be an issue in a file of pids, but it is best practice to always set unless there is a specific reason not to.







share|improve this answer















share|improve this answer



share|improve this answer








edited Aug 4 at 0:40









Peter Mortensen

76348




76348











answered Aug 3 at 20:38









Jesse_b

10.1k12658




10.1k12658







  • 3




    The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
    – Kusalananda
    Aug 3 at 20:52











  • One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
    – Kusalananda
    Aug 3 at 21:09






  • 1




    [ -s pid.txt ] || rm pid.txt to remove if empty, right?
    – ilkkachu
    Aug 3 at 23:48










  • Good catch @ilkkachu, thanks
    – Jesse_b
    Aug 3 at 23:55










  • @ilkkachu Sorry, got the test backwards... duh.
    – Kusalananda
    2 days ago












  • 3




    The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
    – Kusalananda
    Aug 3 at 20:52











  • One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
    – Kusalananda
    Aug 3 at 21:09






  • 1




    [ -s pid.txt ] || rm pid.txt to remove if empty, right?
    – ilkkachu
    Aug 3 at 23:48










  • Good catch @ilkkachu, thanks
    – Jesse_b
    Aug 3 at 23:55










  • @ilkkachu Sorry, got the test backwards... duh.
    – Kusalananda
    2 days ago







3




3




The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
– Kusalananda
Aug 3 at 20:52





The initial test can be removed completely as the read loop won't run if it's an empty file. The rm could be replaced by [ -s pid.txt ] && rm pid.txt to remove the file if it's empty. The inner loop could be replaced by xargs -r kill <pid.txt.
– Kusalananda
Aug 3 at 20:52













One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
– Kusalananda
Aug 3 at 21:09




One could also grep . pid.txt | while read ... if there's empty lines in the pid.txt file that one wants to avoid.
– Kusalananda
Aug 3 at 21:09




1




1




[ -s pid.txt ] || rm pid.txt to remove if empty, right?
– ilkkachu
Aug 3 at 23:48




[ -s pid.txt ] || rm pid.txt to remove if empty, right?
– ilkkachu
Aug 3 at 23:48












Good catch @ilkkachu, thanks
– Jesse_b
Aug 3 at 23:55




Good catch @ilkkachu, thanks
– Jesse_b
Aug 3 at 23:55












@ilkkachu Sorry, got the test backwards... duh.
– Kusalananda
2 days ago




@ilkkachu Sorry, got the test backwards... duh.
– Kusalananda
2 days ago


-

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