Function to simplify grep with an often used log












6














I'm trying make a function that simplifies grepping a log I have to work with on a regular basis.



I'd like to use extended regexp with it pipe and redirect the output, etc.



But I'm having trouble doing this using the standard grep pattern file syntax in the function.



The way I have it set up now is horrible to look at, but gets the job done:



alias mygrep='cat /path/to/logs/my.log | grep'


This allows me to run the following without trouble



mygrep -i -E "WARN|java" |less


Seems like the correct implementation should be something like the following.



function mygrep () {
args=$*
grep "$args" /path/to/logs/my.log
}


However when I use this with the search and pipe parameters above, grep returns an invalid option error.



What am I missing?










share|improve this question




















  • 6




    Try dropping the $args and just saying grep "$@" /path/to/logs/my.log.
    – Tom Hunt
    Oct 20 '15 at 17:06






  • 5




    You might also be interested in What is the difference between $* and $@?
    – terdon
    Oct 20 '15 at 17:33






  • 1




    Not a noobish question at all. This trips up even vets, and at least you did your homework.
    – coteyr
    Oct 20 '15 at 19:09
















6














I'm trying make a function that simplifies grepping a log I have to work with on a regular basis.



I'd like to use extended regexp with it pipe and redirect the output, etc.



But I'm having trouble doing this using the standard grep pattern file syntax in the function.



The way I have it set up now is horrible to look at, but gets the job done:



alias mygrep='cat /path/to/logs/my.log | grep'


This allows me to run the following without trouble



mygrep -i -E "WARN|java" |less


Seems like the correct implementation should be something like the following.



function mygrep () {
args=$*
grep "$args" /path/to/logs/my.log
}


However when I use this with the search and pipe parameters above, grep returns an invalid option error.



What am I missing?










share|improve this question




















  • 6




    Try dropping the $args and just saying grep "$@" /path/to/logs/my.log.
    – Tom Hunt
    Oct 20 '15 at 17:06






  • 5




    You might also be interested in What is the difference between $* and $@?
    – terdon
    Oct 20 '15 at 17:33






  • 1




    Not a noobish question at all. This trips up even vets, and at least you did your homework.
    – coteyr
    Oct 20 '15 at 19:09














6












6








6







I'm trying make a function that simplifies grepping a log I have to work with on a regular basis.



I'd like to use extended regexp with it pipe and redirect the output, etc.



But I'm having trouble doing this using the standard grep pattern file syntax in the function.



The way I have it set up now is horrible to look at, but gets the job done:



alias mygrep='cat /path/to/logs/my.log | grep'


This allows me to run the following without trouble



mygrep -i -E "WARN|java" |less


Seems like the correct implementation should be something like the following.



function mygrep () {
args=$*
grep "$args" /path/to/logs/my.log
}


However when I use this with the search and pipe parameters above, grep returns an invalid option error.



What am I missing?










share|improve this question















I'm trying make a function that simplifies grepping a log I have to work with on a regular basis.



I'd like to use extended regexp with it pipe and redirect the output, etc.



But I'm having trouble doing this using the standard grep pattern file syntax in the function.



The way I have it set up now is horrible to look at, but gets the job done:



alias mygrep='cat /path/to/logs/my.log | grep'


This allows me to run the following without trouble



mygrep -i -E "WARN|java" |less


Seems like the correct implementation should be something like the following.



function mygrep () {
args=$*
grep "$args" /path/to/logs/my.log
}


However when I use this with the search and pipe parameters above, grep returns an invalid option error.



What am I missing?







grep pipe cat function






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 16 at 4:27









Rui F Ribeiro

38.9k1479129




38.9k1479129










asked Oct 20 '15 at 16:55









Kirk Anderson

335




335








  • 6




    Try dropping the $args and just saying grep "$@" /path/to/logs/my.log.
    – Tom Hunt
    Oct 20 '15 at 17:06






  • 5




    You might also be interested in What is the difference between $* and $@?
    – terdon
    Oct 20 '15 at 17:33






  • 1




    Not a noobish question at all. This trips up even vets, and at least you did your homework.
    – coteyr
    Oct 20 '15 at 19:09














  • 6




    Try dropping the $args and just saying grep "$@" /path/to/logs/my.log.
    – Tom Hunt
    Oct 20 '15 at 17:06






  • 5




    You might also be interested in What is the difference between $* and $@?
    – terdon
    Oct 20 '15 at 17:33






  • 1




    Not a noobish question at all. This trips up even vets, and at least you did your homework.
    – coteyr
    Oct 20 '15 at 19:09








6




6




Try dropping the $args and just saying grep "$@" /path/to/logs/my.log.
– Tom Hunt
Oct 20 '15 at 17:06




Try dropping the $args and just saying grep "$@" /path/to/logs/my.log.
– Tom Hunt
Oct 20 '15 at 17:06




5




5




You might also be interested in What is the difference between $* and $@?
– terdon
Oct 20 '15 at 17:33




You might also be interested in What is the difference between $* and $@?
– terdon
Oct 20 '15 at 17:33




1




1




Not a noobish question at all. This trips up even vets, and at least you did your homework.
– coteyr
Oct 20 '15 at 19:09




Not a noobish question at all. This trips up even vets, and at least you did your homework.
– coteyr
Oct 20 '15 at 19:09










1 Answer
1






active

oldest

votes


















11














The following code has $args quoted:



grep "$args" /path/to/logs/my.log


This asks to pass the entire value of that variable as a single
parameter to grep. Thus, if you call mygrep with parameters -i and
-E, grep will in fact receive a single parameter -i -E, which is
indeed invalid.



The following should do it:



function mygrep () {
grep "$@" /path/to/logs/my.log
}


Writing "$@" does the right thing: it's similar to $*, except that
it properly expands each parameter to a single word.






share|improve this answer





















  • This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
    – Kirk Anderson
    Oct 22 '15 at 21:43











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









11














The following code has $args quoted:



grep "$args" /path/to/logs/my.log


This asks to pass the entire value of that variable as a single
parameter to grep. Thus, if you call mygrep with parameters -i and
-E, grep will in fact receive a single parameter -i -E, which is
indeed invalid.



The following should do it:



function mygrep () {
grep "$@" /path/to/logs/my.log
}


Writing "$@" does the right thing: it's similar to $*, except that
it properly expands each parameter to a single word.






share|improve this answer





















  • This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
    – Kirk Anderson
    Oct 22 '15 at 21:43
















11














The following code has $args quoted:



grep "$args" /path/to/logs/my.log


This asks to pass the entire value of that variable as a single
parameter to grep. Thus, if you call mygrep with parameters -i and
-E, grep will in fact receive a single parameter -i -E, which is
indeed invalid.



The following should do it:



function mygrep () {
grep "$@" /path/to/logs/my.log
}


Writing "$@" does the right thing: it's similar to $*, except that
it properly expands each parameter to a single word.






share|improve this answer





















  • This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
    – Kirk Anderson
    Oct 22 '15 at 21:43














11












11








11






The following code has $args quoted:



grep "$args" /path/to/logs/my.log


This asks to pass the entire value of that variable as a single
parameter to grep. Thus, if you call mygrep with parameters -i and
-E, grep will in fact receive a single parameter -i -E, which is
indeed invalid.



The following should do it:



function mygrep () {
grep "$@" /path/to/logs/my.log
}


Writing "$@" does the right thing: it's similar to $*, except that
it properly expands each parameter to a single word.






share|improve this answer












The following code has $args quoted:



grep "$args" /path/to/logs/my.log


This asks to pass the entire value of that variable as a single
parameter to grep. Thus, if you call mygrep with parameters -i and
-E, grep will in fact receive a single parameter -i -E, which is
indeed invalid.



The following should do it:



function mygrep () {
grep "$@" /path/to/logs/my.log
}


Writing "$@" does the right thing: it's similar to $*, except that
it properly expands each parameter to a single word.







share|improve this answer












share|improve this answer



share|improve this answer










answered Oct 20 '15 at 17:08









dhag

11.2k33045




11.2k33045












  • This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
    – Kirk Anderson
    Oct 22 '15 at 21:43


















  • This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
    – Kirk Anderson
    Oct 22 '15 at 21:43
















This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
– Kirk Anderson
Oct 22 '15 at 21:43




This works perfectly, thanks! Also thanks to everyone who responded so cordially and helpfully.
– Kirk Anderson
Oct 22 '15 at 21:43


















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