My understanding is that find traverses the entire file path to locate a string. As a result I cannot understand why the below regex is not working.
find / -regex '^sysconfig$'
Should return /etc/sysconfig.
Even simple regex such as find / -regex 'bin' returns nothing.
Am I missing something very simple?
Just change your regex to,
find / -regex '.*sysconfig$'
OR
find / -regex '.*/sysconfig$'
Because -regex find expression matches the whole name, including the relative path from the current directory. So .* at first will match the preceding characters.
In no regex implementation I'm aware of will the regex ^sysconfig$ match something like:
blah blah sysconfig
The ^ and $ are start-string and end-string anchors, meaning that your test string will only match if it is exactly sysconfig, with no other text on either side. And, in fact, they're not even needed since -regex matches the entire string rather than substrings.
If you want all files ending with sysconfig, just use:
find / - regex '.*sysconfig'
Or use '.*/sysconfig' if you want all files called sysconfig in any directory.
Related
Trying to find a command that is flexible enough to allow for some variations of the string, but not other variations of it.
For instance, I am looking for audio files that have some variation of "rain" in the filename only (rains, raining, rained, rainbow, rainfall, a dark rain cloud, etc), whether at the beginning, end or middle of the filename.
However, this also includes words like "brain", "train", "grain", "drain", "Lorraine", et al, which are not wanted (basically any word that has nothing to do with the concept of rain).
Something like this fails:
find . -name '*rain*' ! -name '*brain*'| more
And I'm having no luck with even getting started on building a successful regex variant because I cannot wrap my mind around regex ... for instance, this doesn't do anything:
# this is incomplete, just a stub of where I was going
# -type f also still includes a directory name
find . -regextype findutils-default -iregex '\(*rain*\)' -type f
Any help would be greatly appreciated. If I could see a regex command that does everything I want it to do, with an explanation of each character in the command, it would help me learn more about regex with the find command in general.
edit 1:
Taking cues from all the feedback so far from jhnc and Seth Falco, I have tried this:
find . -type f | grep -Pi '(?<![a-zA-Z])rain'
I think this pretty much works (I don't think it is missing anything), my only issue with it is that it also matches on occurrences of "rain" further up the path, not only in the file name. So I get example output like this:
./Linux/path/to/radiohead - 2007 - in rainbows/09 Jigsaw Falling Into Place.mp3
Since "rain" is not in the filename itself, this is a result I'd rather not see. So I tried this:
find . -type f -printf '%f\n' | grep -Pi '(?<![a-zA-Z])rain'
That does ensure that only filenames are matched, but it also does not output the paths to the filenames, which I would still like to see, so I know where the file is.
So I guess what I really need is a PCRE (PCRE2 ?) which can take the seemingly successful look-behind method, but only apply it after the last path delimiter (/ since I am on Linux), and I am still stumped.
specification:
match "rain"
in filename
only at start of a word
case-insensitive
assumptions:
define "word" to be sequence of letters (no punctuation, digits, etc)
paths have form prefix/name where prefix can have one or more levels delimited by / and name does not contain /
constraints:
find -iregex matches against entire path (-name only matches filename)
find -iregex must match entirety of path (eg. "c" is only a partial match and does not match path "a/b/c")
method:
find can return matches against non-files (eg. directories). Given definition 6, we would be unable to tell if name is a directory or an ordinary file. To satisfy 2, we can exclude non-files using find's -type f predicate.
We can compare paths found by find against our specification by using find's case-insensitive regex matching predicate (-iregex). The "grep" flavour (-regextype grep) is sufficiently expressive.
Just using 1, a suitable regex is: rain
2+6+7 says we must forbid / after "rain": rain[^/]*$
[/] matches character in set (ie. /)
[^/]: ^ inverts match: ie. character that is not /
* matches preceding match zero or more times
$ constrains preceding match to occur at end of input
3+5 says there must be no immediately preceding word characters: [^a-z]rain[^/]*$
a-z is a shortcut for the range a to z
8 requires matching the prefix explicitly: ^.*[^a-z]rain[^/]*$
^ outside of [...] constrains subsequent match to occur at beginning of input
. matches anything
[^a-z] matches a non-alphabetic
Final command-line:
find . -type f -regextype grep -iregex '^.*[^a-z]rain[^/]*$'
Note: The leading ^ and trailing $ are not actually required, given 8, and could be elided.
exercise for the reader:
extend "word" to non-ASCII characters (eg. UTF-8)
You probably want to use either a character class, word boundary, or just have a negative look behind for alpha characters.
Look Behind
^.+(?<![a-zA-Z])rain[^\/]*$
Matches any instance of rain, but only if it's not following [a-zA-Z], and doesn't have any slashes afterwards. Unfortunately, find doesn't support look ahead or look behind… so we'll use a character class instead.
Character Class
^.+(?:^|[^a-zA-Z])rain[^\/]*$
Matches the start of the line, or a character that isn't [a-zA-Z], then proceeds to match by the characters for rain if it comes immediately after, so long as there are no slashes afterwards.
You can use it in find like this:
find ./ -iregex '.+(?:^|[^a-zA-Z])rain[^\/]*'
The ^ at the start and $ at the end of the pattern are implied when using find with -iregex, so you can omit them.
My question is so simple, but I could not find any solution yet.
I need to find files with the date (string) repeated in their names. For example:
20190101_fl_20190101.nc
20190101_fl_20190104.nc
20190102_fl_20190102.nc
20190102_fl_20190104.nc
I need to find 20190101_fl_20190101.nc and 20190102_fl_20190102.nc.
I have tried
ls 20190[0-9][0-9][0-9]_fl_20190[0-9][0-9][0-9].nc
But, as expected, it finds all possible combinations.
Any help would be highly appreciated.
You can use
find . -type f -regextype posix-extended -regex '.*/(20190[0-9]{3})_fl_\1\.nc$'
The regex matches
.*/ - any chars up to the rightmost / (necessary because the pattern used with find requires a full string match)
(20190[0-9]{3}) - Group 1: 2019 and any three digits
_fl_ - a fixed substring
\1 - backreference to Group 1 value
\.nc - .nc string
$ - end of input.
The -regextype posix-extended option is necessary since the pattern above is POSIX ERE compliant.
According to Wikipedia:
The question mark indicates zero or one occurrences of the
preceding element. For example, colou?r matches both "color" and
"colour".
The asterisk indicates zero or more occurrences of the preceding element. For example, ab*c matches "ac", "abc", "abbc", "abbbc", and
so on.
The plus sign indicates one or more occurrences of the preceding element. For example, ab+c matches "abc", "abbc", "abbbc", and so on,
but not "ac".
However, if I create a file named "colour" and use find -name colou?r to find it, I have no result:
& touch colour
& find -name colou?r
& ...
In the same spirit, If I create a file name ac and launch find -name ab*c, I have no result.
And find -name ab+c does not match abc in bash.
So does bash have a different support of regex than what Wikipedia describes ?
The -name option tests the filename against wildcard patterns (aka glob), not a regular expression. To use a regular expression, use the -regex option:
find . -regex '.*colou?r.*'
Also, make sure you quote these arguments, otherwise the shell will expand them before passing them to find.
I'm trying to search for whole word ending with .properties
So far this works:
find -E . -iregex '.*[:alnum:]+\.properties'
But I want to find only paths like
/some/path/messages.properties
and not
/some/path/messages_en.properties
The previous regex matches "en.properties" So, Im trying to say something like:
.*\/[:alnum:]+\.properties
That is, anything followed by slash then a word and then .properties but the slash part seems not to be working
You can use this regex with anchor $ on RHS and / on LHS to ensure filename is always complete:
find -E . -iregex '.*/[[:alnum:]]+\.properties$'
I need to list all filenames which is having alien.digits
digits can be anytime from 1 to many
but it should not match if its the mixture of any other thing like alien.htm, alien.1php, alien.1234.pj.123, alien.123.12, alien.12.12p.234htm
I wrote:
find home/jassi/ -name "alien.[0-9]*"
But it is not working and its matching everything.
Any solution for that?
I think what you want is
find home/jassi/ -regex ".*/alien\.[0-9]+"
With -name option you don't specify a regular expression but a glob pattern.
Be aware that find expects that the whole path is matched by the regular expression.
Try this: find home/jassi/ -name "alien\.[0-9]+$"
It will match all files that have alien. and end with at least one digit but nothing else than digits. The $ character means end of string.
The * modifier means 0 or more of the previous match, and . means any character, which means it's matching alien.
Try this instead:
alien\.[0-9]+$
The + modifier means 1 or more of the previous match, and the . has been escaped to a literal character, and the $ on the end means "end of string".
You can also add a ^ to the start of the regex if you want to make sure that only files that exactly match your regex. The ^ character means "start of string", so ^alien\.[0-9]+$ will match alien.1234, but it won't match not_an_alien.1234.
It worked for me:
find home/jassi/ type -f -regex ".*/alien.[0-9]+"
I had to provide type -f to check if it's a file , else it would show the directory also of the same name.
Thanks bmk. I just figured out and at the same time you responded exactly the same thing. Great!