I would like to pass the output list of elements of a command as a parameter of another command. I have found some other pages:
How to display the output of a Linux command on stdout and also pipe it to another command?
Use output of bash command (with pipe) as a parameter for another command
but they seem to be more complex.
I just would like to copy a file to every result of a call to the Linux find command.
What is wrong here?:
find . -name myFile 2>&1 | cp /home/myuser/myFile $1
Thanks
This is what you want:
find . -name myFile -exec cp /home/myuser/myFile {} ';'
A breakdown / explanation of this:
find: invoking the find command
.: start search from current working directory.
Since no depth flags are specified, this will search recursively for all subfolders
-name myFile: find files with the explicit name myFile
-exec: for the search results, perform additional commands with them
cp /home/myuser/myFile {}: copies /home/myuser/myFile to overwrite each result returned by find to ; think of {} as where each search result goes.
';': used to separate different commands to be run after find
There are a couple of ways to solve this, depending on whether you need to worry about files with spaces or other special characters in their names.
If none of the filenames have spaces or special characters (they consist only of letters, numbers, dashes, and underscores), then the following is a simple solution that will work. You can use $(command) to execute a command, and substitute the results into the arguments of another command. The shell will split the result on spaces, tabs, or newlines, and for assign each value to $f in turn, and run the command on each value.
for f in $(find . -name myFile)
do
cp something $f
done
If you do have spaces or tabs, you could use find's -exec option. You pass -exec command args, putting {} where you want the filename to be substituted, and ending the arguments with a ;. You need to quote the {} and ; so that the shell doesn't interpret them.
find . -name myFile -exec cp something "{}" \;
Sometimes -exec is not sufficient. For example, in this question, they wanted to use Bash parameter expansion to compute the filename. In order to do that, you need to pass -exec bash -c 'your command', but then you will run into quoting problems with the {} substitution. To solve this, you can use -print0 from find to print the results delimited with null characters (which are invalid in filenames), and pipe it to a while read loop that splits parameters on nulls:
find . -name myFile -print0 | (while read -d $'\0' f; do
cp something "$f"
done)
The pipe will send the output of one program to the input of another. cp does not read from its input stream at the terminal, it merely uses the arguments on the command line.
You want to either use xargs with the pipe or find's exec argument instead of pipes.
find . -name myFile 2>&1 | xargs -I {} cp /home/myuser/myFile {}
Note: option -I {} defines {} as the place holder you could alternatively use someother placeholder if it conflicts with command to be executed.
Related
I hope you can help me with the following problem:
The Situation
I need to find files in various folders and copy them to another folder. The files and folders can contain white spaces and umlauts.
The filenames contain an ID and a string like:
"2022-01-11-02 super important file"
The filenames I need to find are collected in a textfile named ids.txt. This file only contains the IDs but not the whole filename as a string.
What I want to achieve:
I want to read out ids.txt line by line.
For every line in ids.txt I want to do a find search and copy cp the result to destination.
So far I tried:
for n in $(cat ids.txt); do find /home/alex/testzone/ -name "$n" -exec cp {} /home/alex/testzone/output \; ;
while read -r ids; do find /home/alex/testzone -name "$ids" -exec cp {} /home/alex/testzone/output \; ; done < ids.txt
The output folder remains empty. Not using -exec also gives no (search)results.
I was thinking that -name "$ids" is the root cause here. My files contain the ID + a String so I should search for names containing the ID plus a variable string (star)
As argument for -name I also tried "$ids *" "$ids"" *" and so on with no luck.
Is there an argument that I can use in conjunction with find instead of using the star in the -name argument?
Do you have any solution for me to automate this process in a bash script to read out ids.txt file, search the filenames and copy them over to specified folder?
In the end I would like to create a bash script that takes ids.txt and the search-folder and the output-folder as arguments like:
my-id-search.sh /home/alex/testzone/ids.txt /home/alex/testzone/ /home/alex/testzone/output
EDIT:
This is some example content of the ids.txt file where only ids are listed (not the whole filename):
2022-01-11-01
2022-01-11-02
2020-12-01-62
EDIT II:
Going on with the solution from tripleee:
#!/bin/bash
grep . $1 | while read -r id; do
echo "Der Suchbegriff lautet:"$id; echo;
find /home/alex/testzone -name "$id*" -exec cp {} /home/alex/testzone/ausgabe \;
done
In case my ids.txt file contains empty lines the -name "$id*" will be -name * which in turn finds all files and copies all files.
Trying to prevent empty line to be read does not seem to work. They should be filtered by the expression grep . $1 |. What am I doing wrong?
If your destination folder is always the same, the quickest and absolutely most elegant solution is to run a single find command to look for all of the files.
sed 's/.*/-o\n—name\n&*/' ids.txt |
xargs -I {} find -false {} -exec cp {} /home/alex/testzone/output +
The -false predicate is a bit of a hack to allow the list of actual predicates to start with -o (as in "or").
This could fail if ids.txt is too large to fit into a single xargs invocation, or if your sed does not understand \n to mean a literal newline.
(Here's a fix for the latter case:
xargs printf '-o\n-name\n%s*\n' <ids.txt |
...
Still the inherent problem with using xargs find like this is that xargs could split the list between -o and -name or between -name and the actual file name pattern if it needs to run more than one find command to process all the arguments.
A slightly hackish solution to that is to ensure that each pair is a single string, and then separately split them back out again:
xargs printf '-o_-name_%s*\n' <ids.txt |
xargs bash -c 'arr=("$#"); find -false ${arr[#]/-o_-name_/-o -name } -exec cp {} "$0"' /home/alex/testzone/ausgabe
where we temporarily hold the arguments in an array where each file name and its flags is a single item, and then replace the flags into separate tokens. This still won't work correctly if the file names you operate on contain literal shell metacharacters like * etc.)
A more mundane solution fixes your while read attempt by adding the missing wildcard in the -name argument. (I also took the liberty to rename the variable, since read will only read one argument at a time, so the variable name should be singular.)
while read -r id; do
find /home/alex/testzone -name "$id*" -exec cp {} /home/alex/testzone/output \;
done < ids.txt
Please try the following bash script copier.sh
#!/bin/bash
IFS=$'\n' # make newlines the only separator
set -f # disable globbing
file="files.txt" # name of file containing filenames
finish="finish" # destination directory
while read -r n ; do (
du -a | awk '{for(i=2;i<=NF;++i)printf $i" " ; print " "}' | grep $n | sed 's/ *$//g' | xargs -I '{}' cp '{}' $finish
);
done < $file
which copies recursively all the files named in files.txt from . and it's subfiles to ./finish
This new version works even if there are spaces in the directory names or file names.
Why does running this command give me error message: No such file or directory ?
for i in `find ~/desktop -name '*.py'` ; do ./$i ; done
The complete error message makes it much more clear what the problem is:
bash: .//home/youruser/desktop/foo.py: No such file or directory
You can see that there is indeed no such file:
$ .//home/youruser/desktop/foo.py
bash: .//home/youruser/desktop/foo.py: No such file or directory
$ ls -l .//home/youruser/desktop/foo.py
ls: cannot access './/home/youruser/desktop/foo.py': No such file or directory
Here's instead how you can run a file /home/youruser/desktop/foo.py:
$ /home/youruser/desktop/foo.py
Hello World
So to run it in your loop, you can do:
for i in `find ~/desktop -name '*.py'` ; do $i ; done
Here's a better way of doing the same thing:
find ~/desktop -name '*.py' -exec {} \;
or with a shell loop:
find ~/desktop -name '*.py' -print0 | while IFS= read -d '' -r file; do "$file"; done
For an explanation of what ./ is and does, and why it makes no sense here, see this question
Try find and exec option. http://man7.org/linux/man-pages/man1/find.1.html
-exec command ;
Execute command; true if 0 status is returned. All following
arguments to find are taken to be arguments to the command
until an argument consisting of `;' is encountered. The
string `{}' is replaced by the current file name being
processed everywhere it occurs in the arguments to the
command, not just in arguments where it is alone, as in some
versions of find. Both of these constructions might need to
be escaped (with a `\') or quoted to protect them from
expansion by the shell. See the EXAMPLES section for examples
of the use of the -exec option. The specified command is run
once for each matched file. The command is executed in the
starting directory. There are unavoidable security problems
surrounding use of the -exec action; you should use the
-execdir option instead.
-exec command {} +
This variant of the -exec action 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, and (when find is being
invoked from a shell) it should be quoted (for example, '{}')
to protect it from interpretation by shells. The command is
executed in the starting directory. If any invocation with
the `+' form returns a non-zero value as exit status, then
find returns a non-zero exit status. If find encounters an
error, this can sometimes cause an immediate exit, so some
pending commands may not be run at all. This variant of -exec
always returns true.
The paths returned by the find statement will be absolute paths, like ~/desktop/program.py. If you put ./ in front of them, you get paths like ./~/desktop/ which don’t exist.
Replace ./$i with "$i" (the quotes to take care of file names with spaces etc.).
You should use $i and not ./$i
I was doing the same thing this exact moment. I wanted a script to find if there's any flac files in the directory and convert it to opus.
Here is my solution:
if test -n "$(find ./ -maxdepth 1 -name '*.flac' -print -quit)"
then
do this
else
do nothing
fi
OS Linux Mint
Like the title says finally I would like to find and copy all images in a directory.
I found:
find all jpg (or JPG) files in a directory and copy them into the folder /home/joachim/neu2:
find . -iname \*.jpg -print0 | xargs -I{} -0 cp -v {} /home/joachim/neu2
and
find all image files in a direcotry:
find . -name '*' -exec file {} \; | grep -o -P '^.+: \w+ image'
My problem is first of all, I don't really understand the syntax. Could someone explain the code?
And secondly can someone connect the two codes for generating a code that does what I want ;)
Greetings and thanks in advance!
First, understand that the pipe "|" links commands piping the output of the first into the second as an argument. Your two shell codes both pipe output of the find command into other commands (grep and xargs). Let's look at those commands one after another:
First command: find
find is a program to "search for files in a directory hierarchy" (that is the explanation from find's man page). The syntax is (in this case)
find <search directory> <search pattern> <action>
In both cases the search directory is . (that is the current directory). Note that it does not just search the current directory but all its subdirectories as well (the directory hierarchy).
The search pattern accepts options -name (meaning it searches for files the name of which matches the pattern given as an argument to this option) or -iname (same as name but case insensitive) among others.
The action pattern may be -print0 (print the exact filename including its position in the given search directory, i.e. the relative or absolute path to the file) or -exec (execute the given command on the file(s), the command is to be ended with ";" and every instance of "{}" is replaced by the filename).
That is, the first shell code (first part, left of the pipe)
find . -iname \*.jpg -print0
searches all files with ending ".jpg" in the current directory hierarchy and prints their paths and names. The second one (first part)
find . -name '*' -exec file {} \;
finds all files in the current directory hierarchy and executes
file <filename>
on them. File is another command that determines and prints the file type (have a look at the man page for details, man file).
Second command: xargs
xargs is a command that "builds and exectues command lines from standard input" (man xargs), i.e. from the find output that is piped into xargs. The command that it builds and executes is in this case
cp -v {} /home/joachim/neu2"
Option -I{} defines the replacement string, i.e. every instance of {} in the command is to be replaced by the input it gets from file (that is, the filenames). Option -0 defines that input items are not terminated (seperated) by whitespace or newlines but only by a null character. This seems to be necessary when using and the standard way to deal with find output as xargs input.
The command that is built and executed is then of course the copy command with option -v (verbose) and it copies each of the filenames it gets from find to the directory.
Third command: grep
grep filters its input giving only those lines or strings that match a particular output pattern. Option -o tells grep to print only the matching string, not the entire line (see man grep), -P tells it to interpret the following pattern as a perl regexp pattern. In perl regex, ^ is the start of the line, .+ is any arbitrary string, this arbitrary should then be followed by a colon, a space, a number of alphanumeric characters (in perl regex denoted \w+) a space and the string "image". Essentially this grep command filters the file output to only output the filenames that are image files. (Read about perl regex's for instance here: http://www.comp.leeds.ac.uk/Perl/matching.html )
The command you actually wanted
Now what you want to do is (1) take the output of the second shell command (which lists the image files), (2) bring it into the appropriate form and (3) pipe it into the xargs command from the first shell command line (which then builds and executes the copy command you wanted). So this time we have a three (actually four) stage shell command with two pipes. Not a problem. We already have stages (1) and (3) (though in stage (3) we need to leave out the -0 option because the input is not find output any more; we need it to treat newlines as item seperators).
Stage (2) is still missing. I suggest using the cut command for this. cut changes strings py splitting them into different fields (seperated by a delimiter character in the original string) that can then be rearranged. I will choose ":" as the delimiter character (this ends the filename in the grep output, option -d':') and tell it to give us just the first field (option -f1, essentialls: print only the filename, not the part that comes after the ":"), i.e. stage (2) would then be
cut -d':' -f1
And the entire command you wanted will then be:
find . -name '*' -exec file {} \; | grep -o -P '^.+: \w+ image' | cut -d':' -f1 | xargs -I{} cp -v {} /home/joachim/neu2
Note that you can find all the man pages for instance here: http://www.linuxmanpages.com
I figured out a command only using awk that does the job as well:
find . -name '*' -exec file {} \; |
awk '{
if ($3=="image"){
print substr($1, 0, length($1)-1);
system("cp " substr($1, 0, length($1)-1) " /home/joachim/neu2" )
}
}'
the substr($1, 0, length($1)-1) is needed because in first column file returns name;
The above answer is really good. but it could take longer if it a huge directory.
here is a shorter version of it , if you already know your file extension
find . -name \*.jpg | cut -d':' -f1 | xargs -I{} cp --parents -v {} ~/testimage/
Here's another one which works like a charm.
It adds the EPOCH time to prevent overwriting files with the same name.
cd /media/myhome/'Local station'/
find . -path ./jpg -prune -o -type f -iname '*.jpg' -exec sh -c '
for file do
newname="${file##*/}"
newname="${newname%.jpg}"
mv -T -- "$file" "/media/myhome/Local station/jpg/$newname-$(date +%s).jpg"
done
' find-sh {} +
cd ~/
It's been designed by Kamil in this post here.
Find a specific type file from a directory:
find /home/user/find/data/ -name '*' -exec file {} \; | grep -o -P '^.+: \w+ image'
Copy specific type of file from one directory to another directory:
find /home/user/find/data/ -name '*' -exec file {} \; | grep -o -P '^.+: \w+ image' | cut -d':' -f1 | xargs -I{} cp -v {} /home/user/copy/data/
I want to insert a line into the start of multiple specified type files, which the files are located in current directory or the sub dir.
I know that using
find . -name "*.csv"
can help me to list the files I want to use for inserting.
and using
sed -i '1icolumn1,column2,column3' test.csv
can use to insert one line at the start of file,
but now I do NOT know how to pipe the filenames from "find" command to "sed" command.
Could anybody give me any suggestion?
Or is there any better solution to do this?
BTW, is it work to do this in one line command?
Try using xargs to pass output of find and command line arguments to next command, here sed
find . -type f -name '*.csv' -print0 | xargs -0 sed -i '1icolumn1,column2,column3'
Another option would be to use -exec option of find.
find . -type f -name '*.csv' -exec sed -i '1icolumn1,column2,column3' {} \;
Note : It has been observed that xargs is more efficient way and can handle multiple processes using -P option.
This way :
find . -type f -name "*.csv" -exec sed -i '1icolumn1,column2,column3' {} +
-exec do all the magic here. The relevant part of man find :
-exec command ;
Execute command; true if 0 status is returned. All following arguments
to find are taken to be arguments to the command until an argument consisting
of `;' is encountered. The string `{}' is replaced by the current file name
being processed everywhere it occurs in the arguments to the command, not just
in arguments where it is alone, as in some versions of find. Both of
these constructions might need to be escaped (with a `\') or quoted to protect
them from expansion by the shell. See the EXAMPLES section for examples of
the use of the -exec option. The specified command is run once for each
matched file. The command is executed in the starting directory. There
are unavoidable security problems surrounding use of the -exec action;
you should use the -execdir option instead
I use command of find, for example:
find . -name "*.log" -exec grep "running" {} \;
why the command of find need {} , a blank and \?
This is because of the -exec parameter: the {} is a placeholder for the file that will be passed to the command.
the semicolon (;) tells find that the -exec argument list is over, but since ; is also a shell operator, you need to escape it so that it reaches find: \;
-exec works like this: for every file that is found, the first argument after -exec (the command) is executed and all parameters up until the ; are passed as arguments to the command. The {} is then replaced by the current filename that is found by find.
{} is a placeholder for path, which find replaces with the actual found path.
\; terminates find's exec arguments. Without \ shell would treat it as shell statement terminator, hence it needs to be quoted with \ for the shell to pass ; it to find.
I'd say that ; was an unfortunate choice for find exec command terminator.
Note that {} \; sequence can be replaced with {} +:
-exec command {} +
This variant of the -exec action 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 invoca‐
tions 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.
Just read the manpages
-exec command ;
Execute command; true if 0 status is returned. All following
arguments to find are taken to be arguments to the command until
an argument consisting of `;' is encountered. The string `{}'
is replaced by the current file name being processed everywhere
it occurs in the arguments to the command, not just in arguments
where it is alone, as in some versions of find. Both of these
constructions might need to be escaped (with a `\') or quoted to
protect them from expansion by the shell. See the EXAMPLES sec‐
tion for examples of the use of the -exec option. The specified
command is run once for each matched file. The command is exe‐
cuted in the starting directory. There are unavoidable secu‐
rity problems surrounding use of the -exec action; you should
use the -execdir option instead.
The backslash is an escape to protect the semicolon from being misinterpreted.
The braces are placeholders for the full path outputted by find.