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Is there a way to get just the file's owner and group, separated by space in unix shell?
I'm trying to write a script to find the owner of all the files in a directory and print it (in a specific format, can't use ls -la).
ls -l | awk '{print $3, $4 }'
That'll do it
Use the stat command, if available on your version of UNIX:
$ stat -c "%U %G" /etc/passwd
root root
or, to do this operation for all files in a directory and print the name of each file too:
$ stat -c "%n %U %G" *
GNU find has the -printf option which will do this for you:
# if you want just the files in the directory, no recursion
find "$dir" -maxdepth 1 -type f -printf "%u %g\n"
# if you want all the files from here down
find "$dir" -type f -printf "%u %g\n"
# if you need the filename as well for disambiguation, stick a %f in there
find "$dir" -maxdepth 1 -type f -printf "%u %g %f\n"
Other systems might have this as gfind.
ls -l | cut -f3,4 -d" " | tail -n +2
Related
I want to create a function in shell programming that gets 2 parameters, directory-name and file-name and that does the following: it searches starting in the given directory-name for the file-name and then goes in all subdirectories of the directory-name to continue the search. I want the output to be every parent-directory where the file-name has been found, sorted using the file-name size.
Help would be much appreciated, thanks.
not sure about which Unix you asked for, but for Linux and maybe common Unix systems:
find <directory> -name "<filename>" -ls | sort -k 7 -n -r | awk '{print $NF}' | xargs -n 1 dirname
sort => sort by file size (the 7th column of find output is filesize)
awk => print the filename full path
dirname => get parent directory of the matched file
Example:
# Find parent directory of all types.h under /usr/include, sorted by file size in desc order
$ find /usr/include/ -name "types.h" -ls | sort -k 7 -n -r | awk '{print $NF}' | xargs -n 1 dirname
/usr/include/x86_64-linux-gnu/bits
/usr/include/x86_64-linux-gnu/sys
/usr/include/c++/7/parallel
/usr/include/rpc
/usr/include/linux/sched
/usr/include/linux/iio
/usr/include/linux
/usr/include/asm-generic
/usr/include/x86_64-linux-gnu/asm
I have a find command combined with exec grep and a printf option :
find -L /home/blast/dirtest -maxdepth 3 **-exec grep -q "pattern" {} \;** -printf '%y/#/%TY-%Tm-%Td %TX/#/%s/#/%f/#/%l/#/%h\n' 2> /dev/null
Result :
f/#/2018-01-01 10:00:00/#/191/#/filee.xml/#//#//home/blast/dirtest/01/05
I need the printf to get all the desired file informations at once (date, type size etc)
The above command works fine. But the exec option is too slow comparing to xargs.
I tryed to do the same with xarg but I did not succeed.
Any Idea on how to acheive that ? using the xargs command keeping the desired printf or similar .
Thanks
Your code is:
find -L /home/blast/dirtest -maxdepth 3 \
-exec grep -q "pattern" {} \; \
-printf '%y/#/%TY-%Tm-%Td %TX/#/%s/#/%f/#/%l/#/%h\n' 2> /dev/null
This invokes a new grep process for each file.
If you are using GNU utilities, you can reduce the number of grep processes by something like:
(
format=\''%y/#/%TY-%Tm-%Td %TX/#/%s/#/%f/#/%l/#/%h\n'\'
find -L /home/blast/dirtest -maxdepth 3 -print0 |\
xargs -0 grep -l -Z "pattern" |\
xargs -0 sh -c 'find "$#" -printf '"$format" --
) 2>/dev/null
for clarity, store the formatstring in a variable
use -print0 / -0 / -Z options to enable null-delimited data
generate initial filelist with find
filter on "pattern" with grep (use of xargs minimises the number of times grep gets called)
feed the filtered filelist into another xargs to run a minimal number of find -printf
in second xargs, call a subshell so that extra arguments can be appended (find requires the paths to precede the operators)
dummy second argument (--) to the sh -c invocation prevents the first filename being lost due to assignment to $0
To do it exactly how you want:
find -L /home/blast/dirtest/ -maxdepth 3 \
-printf '%p#%y/#/%TY-%Tm-%Td %TX/#/%s/#/%f/#/%l/#/%h\n' \
> tmp.out
cut -d# -f1 tmp.out \
| xargs grep -l "pattern" 2>/dev/null \
| sed 's/^/^/; s/$/#/' \
| grep -f /dev/stdin tmp.out \
| sed 's/^.*#//'
This operates under the assumption that you have no character # in your file names.
What it does is avoid the grep at first and just dump all the files with the requested metadata to a temporary file.
But it also prefixes each line with the full path (%p#).
Then we extract (cut) the full paths out of this list and list the files which contains the pattern (xargs grep).
We then use sed to prefix each such file name with ^ and suffix it with #, which makes it a greppable pattern in our tmp.out file.
Then we use this pattern (grep -f /dev/stdin) to extract only those paths from the big list in tmp.out.
Now all that's left is to remove the artificial full path we prefixed using the last sed command.
Seeing how you used /home, there's a good chance you're on Linux, which, if you're willing to accept some output format changes, allows you to do it somewhat more elegantly:
find -L /home/blast/dirtest/ -maxdepth 3 \
| xargs grep -l "pattern" 2>/dev/null \
| xargs stat --printf '%F/#/%y/#/%s/#/%n\n'
The output of stat --printf is different from that of find -printf (and from that of MacOS' stat -f), but it's the same information.
Do note, however, that because you passed -L to find, and you're grepping the result:
The results are limited to file types which can be grepped, so they will never be directories, links, etc..
If you stumble upon a broken link, it will not be in the output because it cannot be grepped.
I'v found an intresting thing about the -exec option.
We could run the grep once using the exec with the plus-sign (+)
-exec command {} +
This variant of the -exec option runs the specified command on the selected files, but the command line is built by appending each selected file name at the end; the total
number of invocations of the command will be much less than the number of matched files. The command line is built in much the same way that xargs builds its command
lines. Only one instance of ’{}’ is allowed within the command. The command is executed in the starting directory.
That means if I change this :
-exec grep -l 'pattern' {} \;
By this ( replace the semicolon with the plus signe ):
-exec grep -l 'pattern' {} \+
Will improve the performance significantly.
Then I can pipe only one xargs for the format printing needs only.
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find . -name "recovery_script" | xargs
I try to execute but it only prints it. How can I run it parallel ?
find . -name "recovery_script" | xargs -n1 -P8 sh
for 8 processes in parallel.
Provided there are at least 8 places where "recovery_script" can be found.
The -n1 argument is necessary to feed one argument at a time to sh. Otherwise, xargs will feed a reasonable number of arguments all at once to sh, meaning it's trying to execute something like
sh dir1/recovery_script dir2/recovery_script dir3/recovery_script ...
instead of
sh dir1/recovery_script
sh dir2/recovery_script
sh dir3/recovery_script
...
in parallel.
Bonus: your command can be longer than just a single command, including options. I often use nice to allow other processes to still continue without problems:
find . -name "recovery_script" | xargs -n1 -P8 nice -n19
where -n19 is an option to nice, not to xargs.
(Aside: if you ever use wildcards for -name in find, use the -print0 option to find, and the -0 option to xargs: that separates output and input by the null character, instead of whitespace (since the latter may be part of the filename). Since you search for the full name here, that is not a problem.)
From the xargs manual page:
SYNOPSIS: xargs ... [command [initial-arguments]]
and
... and executes the command (default is /bin/echo) one or more times with any initial-arguments followed by items read from standard input.
The default behaviour is thus to echo whatever arguments you give to xargs. Providing a command like sh (perhaps depending on what executable you're trying to run) then works.
This solution is not using xargs but a simple bash script. Maybe it can help:
#!/bin/sh
for i in $(find -name recovery_script)
do
{
echo "Started $i"
$i
echo "Ended $i"
} &
done
wait
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I need a unix command to list all files that contains 'foo' in their name ?
We have two commands that do that : grep command and find command !!
what's the best?
Thanks
The find command by itself suffices (unless you want to include files in directories whose name includes "foo"):
find / -type f -name '*foo*'
That checks the leaf name (last part) of the pathnames. If you piped the result of find through grep in a similar way:
find / -type f | grep foo
it would match those files, as well as all files (and directories) inside directories whose name includes "foo".
To filter the list in a more interesting way, you can use grep, which supports regular expressions and other features. For example, you could do
find / -type f | grep -i foo
to match "foo" ignoring case.
But if you want to look at the contents of files, that is grep-specific:
find / -type f -exec grep foo {} +
Further reading:
find
grep
Use find to list all files on the system.
Pair that up with grep to search for a specific file name.
like this:
find / -type f -exec grep -i -r "*foo*" {}
How can I delete from directory2 and directory3 some files in the same time using the find command?
Some files of directory1 valides the same characteristics of the files in the 2 others directory and directories 1,2,3 figures in the directory0.
I suppose you meant:
(cd directory1 | find -iname 'somename' -print0) |
tee >(cd directory2 && xargs -0 rm -fvi) |
tee >(cd directory3 && xargs -0 rm -fvi)
ad libitum? But I'll make the answer more specific once you do your question
To find (From the man examples)
find / -newerct '1 minute ago' -print
Print out a list of all the files whose inode change
time is more recent than the current time minus one minute
To remove
find / -newerct '1 minute ago' -print | xargs rm