Works here: 'awk.js.org/`
but not in openwrt's awk, which returns the error message:
awk: bad regex '^(server=|address=)[': Missing ']'
Hello everyone!
I'm trying to use an awk command I wrote which is:
'!/^(server=|address=)[/][[:alnum:]][[:alnum:]-.]+([/]|[/]#)$|^#|^\s*$/ {count++}; END {print count+0}'
Which counts invalid lines in a dns blocklist (oisd in this case):
Input would be eg:
server=/0--foodwarez.da.ru/anyaddress.1.1.1
serverspellerror=/0-000.store/
server=/0-24bpautomentes.hu/
server=/0-29.com/
server=/0-day.us/
server=/0.0.0remote.cryptopool.eu/
server=/0.0mail6.xmrminingpro.com/
server=/0.0xun.cryptopool.space/
Output for this should be "2" since there are two lines that don't match the criteria (correctly formed address, comments, or blank lines).
I've tried formatting the command every which way with [], but can't find anything that works. Does anyone have an idea what format/syntax/option needs adjusting?
Thanks!
To portably include - in a bracket expression it has to be the first or last character, otherwise it means a range, and \s is shorthand for [[:space:]] in only some awks. This will work in any POSIX awk:
$ awk '!/^(server=|address=)[/][[:alnum:]][[:alnum:].-]+([/]|[/]#)$|^#|^[[:space:]]*$/ {count++}; END {print count+0}' file
2
Per #tripleee's comment below if your awk is broken such that a / inside a bracket expression isn't treated as literal then you may need this instead:
$ awk '!/^(server=|address=)\/[[:alnum:]][[:alnum:].-]+(\/|\/#)$|^#|^[[:space:]]*$/ {count++}; END {print count+0}' file
2
but get a new awk, e.g. GNU awk, as who knows what other surprises the one you're using may have in store for you!
'!/^(server=|address=)[/][[:alnum:]][[:alnum:]-.]+([/]|[/]#)$|^#|^\s*$/ {count++}; END {print count+0}'
- has special meaning inside [ and ], it is used to denote range e.g. [A-Z] means uppercase ASCII letter, use \ escape sequence to make it literal dash, let file.txt content be
server=/0--foodwarez.da.ru/anyaddress.1.1.1
serverspellerror=/0-000.store/
server=/0-24bpautomentes.hu/
server=/0-29.com/
server=/0-day.us/
server=/0.0.0remote.cryptopool.eu/
server=/0.0mail6.xmrminingpro.com/
server=/0.0xun.cryptopool.space/
then
awk '!/^(server=|address=)[/][[:alnum:]][[:alnum:]\-.]+([/]|[/]#)$|^#|^\s*$/ {count++}; END {print count+0}' file.txt
gives output
2
You might also consider replacing \s using [[:space:]] in order to main consistency.
(tested in GNU Awk 5.0.1)
Related
I have a file having the following structure
destination list
move from station d-435-435 to point place1
move from station d-435-435 to point place2
move from mainpoint
I want to extract the word "d-435-435"(Only the first match, this need not be same value always) in between the words "from station" and "to point"
How can I achieve this?
What I have tried so far?
id=$(sed 's/.*from station \(.*\) to.*/\1/' input.txt)
But this returns the following value: destination list d-435-435 move from mainpoint
1st solution: With your shown samples, please try following GNU awk code. Using match function of awk program here to match regex rom station\s+\S+\s+to point to get requested value by OP then removing from station\s+ and \s+to point from matched value and printing required value.
awk '
match($0,/from station\s+\S+\s+to point/){
val=substr($0,RSTART,RLENGTH)
gsub(/from station\s+|\s+to point/,"",val)
print val
exit
}
' Input_file
2nd solution: Using GNU grep please try following. Using -oP option to print matched portion and enabling PCRE regex respectively here. Then in main grep program matching string from station followed by space(s) then using \K option will make sure matched part before \K is forgotten(since e don't need this in output), Then matching \S+(non space values) followed by space(s) to point string(using positive look ahead here to make sure it only checks its present or not but doesn't print that).
grep -oP -m1 'from station\s+\K\S+(?=\s+to point)' Input_file
If GNU sed is available, how about:
id=$(sed -nE '0,/from station.*to/ s/.*from station (.*) to.*/\1/p' input.txt)
The -n option suppress the print unless the substitution succeeds.
The condition 0,/pattern/ is a flip-flop operator and it returns false
after the pattern match succeeds. The 0 address is a GNU sed extension which
makes the 1st line to match against the pattern.
With awk you can write the before and after conditions of
field $4, where d-435-435 is, and then print this field only the first match and exit with exit after print statement:
awk '$2=="from" && $3=="station" && $5=="to" && $6=="point" {print $4; exit}' file
d-435-435
or using GNU awk for the 3rd arg to match():
awk 'match($0,/from station\s+(.*)\s+to point/,a){print a[1];exit}' file
d-435-435
The regexp contains a parenthesis, so the integer-indexed element of array a[1] contain the portion of string between from station followed by space(s) \s+ and space(s) \s+ followed byto point.
This might work for you (GNU sed):
sed -nE '/.*station (\S+) to point.*/{s//\1/;H;x;/\n(\S+)\n.*\1/{s/\n\S+$//;x;d};x;p}' file
Turn off implicit printing and on extended regexps command line options -nE.
If a line matches the required criteria, extract the required string, append a copy to the hold space, check if the match has already been seen and if not print it. If the match has been seen, remove it from the hold space.
Otherwise, do not print anything.
This should work in any sed:
sed -e '/.*from station \([^ ]*\) to .*/!d' -e 's//\1/' -e q file
Consider the following input:
$ cat a
d:\
$ cat a.awk
{ sub("\\", "\\\\"); print $0 }
$ cat a_double.awk
{ sub("\\\\", "\\\\"); print $0 }
Now running cat a | awk -f a.awk gives
d:\
and running cat a | awk -f a_double.awk gives
d:\\
and I expect exactly the other way around. How should I interpret this?
$ awk -V
GNU Awk 4.1.4, API: 1.1 (GNU MPFR 4.0.1, GNU MP 6.1.2)
Yes, its expected behavior of awk. When you run sub("\\", "\\\\") in your first script, in sub's inside "(double quotes) since we are NOT using / for matching pattern we need to escape first \(actual literal character) then for escaping we are using \ so we need to escape that also, hence it will become \\\\
\\ \\
| |
| |
first 2 chars are denoting escaping next 2 chars are denoting actual literal character \
Which is NOT happening your 1st case hence NO match so no substitution in it, in your 2nd awk script you are doing this(escaping part in regex matching section of sub) hence its matching \ perfectly.
Let's see this by example and try putting ... for checking purposes.
When Nothing happens: Since no match on
awk '{sub("\\", "....\\\\"); print $0}' Input_file
d:\
When pattern matching happens:
awk '{sub("\\\\", "...\\\\"); print $0}' Input_file
d:...\\
From man awk:
gsub(r, s [, t])
For each substring matching the regular expression r in the string t,
substitute the string s, and return the number of substitutions.
How could we could do perform actual escaping part(where we need to use only \ before character only once)? Do mention your regexp in /../ in first section of sub like and we need NOT to double escape \ here.
awk '{sub(/\\/,"&\\")} 1' Input_file
The first arg to *sub() is a regexp, not a string, so you should use regexp (/.../) rather than string ("...") delimiters. The former is a literal regexp which is used as-is while the latter defines a dynamic (or computed) regexp which forces awk to interpret the string twice, the first time to convert the string to a regexp and the second to use it as a regexp, hence double the backslashes needed for escaping. See https://www.gnu.org/software/gawk/manual/gawk.html#Computed-Regexps.
In the following we just need to escape the backslash once because we're using a literal, rather than dynamic, regexp:
$ cat a
d:\
$ awk '{sub(/\\/,"\\\\")}1' a
d:\\
Your first script would rightfully produce a syntax error in a more recent version of gawk (5.1.0) since "\\" in a dynamic regexp is equivalent to /\/ in a literal one and in that expression the backslash is escaping the final forward slash which means there is no final delimiter:
$ cat a.awk
{ sub("\\", "\\\\"); print $0 }
$ awk -f a.awk a
awk: a.awk:1: (FILENAME=a FNR=1) fatal: invalid regexp: Trailing backslash: /\/
I have tried multiple google searches, but none of the proposed answers are working for my example below. NF should be 3, but I keep getting 1.
# cat a
1^%2^%3
# awk -F^% '{print NF}' a
1
# awk -F'^%' {print NF}' a
1
awk -F "^%" {print NF}' a
1
The -F variable in awk takes a regular expression as its value. So the value ^ is interpreted as a special anchor regex pattern which need to be deprived of its special meaning. So you escape it a with a literal backslash \ character
awk -F'\\^%' '{ print NF }'
from GNU Awk manual for Escape Sequences
The backslash character itself is another character that cannot be included normally; you must write \\ to put one backslash in the string or regexp. Thus, the string whose contents are the two characters " and \ must be written \"\\.
You should escape ^ to remove its special meaning which is getting used as a regex by field separator.Once you escape ^ by doing \\^ it will be treated as a normal/literal character and then ^% will be considered as string and you will get answer as 3.
awk -F'\\^%' '{print NF}' Input_file
Here is one nice SO link which you could take it as an example too for better understanding, it doesn't talk about specifically ^ character but it talks about how to use escape sequence in field separator in awk.
https://stackoverflow.com/a/44072825/5866580
Using awk, I want to print all lines that have a string in the first column that starts with 22_
I tried the following, but obviously * does not work as a wildcard in awk:
awk '$1=="22_*" {print $0}' input > output
Is this possible in awk?
Let's start with a test file:
$ cat >file
22_something keep
23_other omit
To keep only lines that start with 22_:
$ awk '/^22_/' file
22_something keep
Alternatively, if you prefer to reference the first field explicitly, we could use:
$ awk '$1 ~ /^22_/' file
22_something keep
Note that we don't have to write {print $0} after the condition because that is exactly the default action that awk associates with a condition.
At the start of a regular expressions, ^ matches the beginning of a line. Thus, if you want 22_ to occur at the start of a line or the start of a field, you want to write ^22_.
In the condition $1 ~ /^22_/, note that the operator is ~. That operator tells awk to check if the preceding string, $1, matches the regular expression ^22_.
Chosen answer does not answer how to use a wildcard in awk, which is achieved using .* (instead of *):
awk '$1=="22_.*" {print $0}' input > output
emphasized textI have some text like
CreateMainPageLink("410",$objUserData,$mnt[139]);
from which i want to extract the number 139 after the occurrence of mnt with gawk. I tried the following expression (within a pipe expression to be used on a result of a grep)
gawk '{FS="[\[\]]";print NF}'
to print the number of fields. If my field separators were [ and ] I expect to see the number 3 printed out (three fields; one before the opening rectangular bracket, one after, and the actual number I want to extract). What I get instead is one field, corresponding to the full line, and two warnings:
gawk: warning: escape sequence `\[' treated as plain `['
gawk: warning: escape sequence `\]' treated as plain `]'
I was following the example given here, but obviously there is some problem/error with my expression.
Using the following two expressions also do not work:
gawk '{FS="[]"}{print NF;}'
gawk: (FILENAME=- FNR=1) fatal: Unmatched [ or [^: /[]/
and
gawk '{FS="\[\]"}{print NF;}'
gawk: warning: escape sequence `\[' treated as plain `['
gawk: warning: escape sequence `\]' treated as plain `]'
gawk: (FILENAME=- FNR=1) fatal: Unmatched [ or [^: /[]/
gawk -F[][] '{ print $0" -> "$1"\t"$2; }'
$ gawk -F[][] '{ print $0" -> "$1"\t"$2; }'
titi[toto]tutu
titi[toto]tutu -> titi toto
1) You must set the FS before entering the main parsing loop. You could do:
awk 'BEGIN { FS="[\\[\\]]"; } { print $0" -> "$1"\t"$2; }'
Which executes the BEGIN clause before parsing the file.
I have to escape the [character twice: one because it is inside a quoted string. And another once because gawk mandate it inside a bracket expression.
I personnaly prefer to use the -F flag which is less verbose.
2) FS="[\[\]]" is wrong, because you are inside a quoted string, this escape the character inside the string. Awk will see: [[]] which is an invalid bracket expression.
3) FS="[]" is wrong because it is an empty bracket expression trying to match nothing
4) FS="\[\]" is wrong again because it is error 2) and 3) together :)
gawk manual says: The regular expressions in awk are a superset of the POSIX specification. This is why you can use either: [\\[\\]] or [][]. The later being the posix way.
To include a literal ']' in the list, make it the first character
See:
Posix Regex specification:
http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html#tag_09_04
Posix awk specification:
http://pubs.opengroup.org/onlinepubs/009695399/utilities/awk.html
Gnu Awk manual:
http://www.gnu.org/software/gawk/manual/gawk.html#Bracket-Expressions
FS="[]" Here it looks for data inside the [] and there are none.
To use square brackets you need to write them like this [][]
This is also wrong gawk '{FS="[\[\]]";print NF}' you need FS as a variable outside expression.
Eks
echo 'CreateMainPageLink("410",$objUserData,$mnt[139]);' | awk -F[][] '{print $2}'
139
Or
awk '{print $2}' FS=[][]
Or
awk 'BEGIN {FS="[][]"} {print $2}'
All gives 139
Edit: gawk '{FS="[\[\]]";print NF}' Here you print number of fields NF and not value of it $NF. Anyway it will not help, since dividing your data with [] gives ); as last filed, use this awk '{print $(NF-1)}' FS=[][] to get second last filed.
Do you need awk? You can get the value via sed like this:
# echo 'CreateMainPageLink("410",$objUserData,$mnt[139]);' | sed -n 's:.*\[\([0-9]\+\)\].*:\1:p'
139