i am trying to find directory or file that ends in any 3 characters with using
ls -l /etc | grep ???$
and this doesnt work,,
what should I type to find any directory of files that ends with 3 or 4 or 5 or 6 or 7 ... characters?
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Are your three characters any characters, or three specific ones? If they are any characters, then the question is the same as "find names that are at least three characters long". Right? – Kusalananda Sep 30 '19 at 05:31
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Do you mean that the rest of the file name may contain non-characters, while you want the end of the files to contain 3 to 7 characters? How do you define a non-character? Is that sequence of bytes forming valid characters in the current locale encoding? See also How to create string with invalid unicode characters, in Zsh? for other interpretations – Stéphane Chazelas Sep 30 '19 at 05:57
3 Answers
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find /etc -maxdepth 1 -regextype egrep -regex '.*/.{3}$'
This will find file or directory names in /etc/ that are exactly 3 characters long.
find /etc -maxdepth 1 -regextype egrep -regex '.*/.{3,}$'
And this will find files or directories in /etc/ that are a minimum of 3 characters long.
find /etc -maxdepth 1 -regextype egrep -regex '.*/.{3,7}$'
And this will find files or directories in /etc that are anywhere from 3 to 7 characters long.
The -maxdepth 1 prevents find from searching sub-directories of /etc.
If you want to restrict the match to directories only, add -type d after the -maxdepth 1. For regular files, use -type f.
If you intend to do anything with the files/dirs found, you can use find's -exec option. e.g.
find /etc -maxdepth 1 -regextype egrep -regex '.*/.{3,7}$' -exec du -sch {} +
or xargs (but use NUL separators to avoid problems with spaces, newlines, etc in filenames). This allows you to use any tool that can process NUL-separated input in the pipeline before xargs. e.g.:
find /etc -maxdepth 1 -regextype egrep -regex '.*/.{3,7}$' -print0 |
head -z -n 10 |
xargs -0r ls -ld
cas
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To list the names in a single directory (i.e. not recursively) that contain at least three characters, you may use any of the globbing patterns *???, ???* or *???*. Each ? matches a single character, while * matches any number of characters.
To list such names under /etc with ls:
ls -ld /etc/*???
or simply,
printf '%s\n' /etc/*???
If you want to list the names that end in three specific characters (e.g. xyz), then use *xyz as the pattern.
To search for such names recursively, you may (in bash) use shopt -s globstar to enable the ** globbing pattern (matches recursively down into subdirectories) and then...
ls -ld /etc/**/*???
The ** pattern is enabled by default in the zsh shell.
To do something with these names (other than just calling ls), use a loop:
shopt -s globstar
for pathname in /etc/**/*???; do
# use "$pathname" to do something
done
In the dash shell or plain sh, the equivalent of this loop would be
find /etc -name '*???' -exec sh -c '
for pathname do
# use "$pathname" to do something
done' sh {} +
Related:
Your use of grep shows that you are confusing regular expressions with filename globbing patterns. In a regular expression, a dot (.) matches any one single character, while ? matches just the character ? (at least in basic regular expressions, which is what grep uses by default).
Filename patterns are also always anchored, so there's no need to explicitly anchor the pattern with $ as in a regular expression (the pattern must match the complete filename though, so xyz matches exactly that name while *xyz matches any filename ending in xyz).
Related:
Kusalananda
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Note that in most shells,
?also matches on every byte that doesn't form part of valid characters. – Stéphane Chazelas Oct 01 '19 at 20:00
