I have a bash script I cannot get working. I am a dead set beginner in bash this is actually the first script I've ever used. I'm trying to get omxplayer to play a list of files in a directory. When the script runs I get feedback showing the file then the error that there is no such file or directory. Please help me?
#!/bin/sh
find /media/pi/88DC-E668/MP3/ -name "*.mp3" -exec PLAY={} \;; omxplayer "$PLAY";
This is the echo:
find: `PLAY=/media/pi/88DC-E668/MP3/Dance.mp3': No such file or directory
find: `PLAY=/media/pi/88DC-E668/MP3/Whitemary.mp3': No such file or directory
find: `PLAY=/media/pi/88DC-E668/MP3/Limo.mp3': No such file or directory
find: `PLAY=/media/pi/88DC-E668/MP3/Silo.mp3': No such file or directory
File "" not found.
Easy way:
find /media/pi/88DC-E668/MP3 -name \*.mp3 -exec omxplayer {} \;
or
while IFS= read -r -d '' mp3
do
omxplayer "$mp3"
done < <(find /media/pi/88DC-E668/MP3 -name \*.mp3 -print0)
or
find /media/pi/88DC-E668/MP3 -name \*.mp3 -print0 | xargs -0 -n1 omxplayer
You can omit the -n1 if the omxplayer could handle multiple filenames. In such case the 1st could be written as:
find /media/pi/88DC-E668/MP3 -name \*.mp3 -exec omxplayer {} +
but the simplest probably will be
#shopt -s globstar #the default is on
for mp3 in /media/pi/88DC-E668/MP3/{,**/}*.mp3
do
omxplayer "$mp3"
done
EDIT I stand corrected, but won't delete the answer as you can also learn from the mistakes of others. See comment and rather use this answer :)
So please don't do it like this, as this is a typical "happy path" solution - meaning: it works if you know what you're doing and you know your paths (e.g. that they don't contain spaces). I keep forgetting that many people don't know yet that spaces in paths are evil.
Just use xargs to pass what you found to your player like this:
#!/bin/sh
find /media/pi/88DC-E668/MP3/ -name "*.mp3" | xargs omxplayer
The -exec foo part means run the command foo for each path found.
In your case, -exec PATH={}, the {} part is replaced with the path name, ending up with something like -exec PATH=/media/pi/88DC-E668/MP3/Dance.mp3, and so then find tries to run the command PATH=/media/pi/88DC-E668/MP3/Dance.mp3 which fails because there isn't actually any such program to execute.
xargs is the usual way to do what you're trying to do, as described in another comment already.
You could also do:
find /media/pi/88DC-E668/MP3/ -name \*.mp3 |
while read f; do
omxplayer "$f"
done
Related
I am currently working on an auto grading script for a class project. It has to be able to search any number of given directories lets say
for example
usr/autograder/jdoe/
jdoe contains two files house.c and readme.txt.
I need to create a file in jdoe called jdoe.pdf
Currently i'm using this line of code below to get the path to where i need to create the file. Where $1 is user input of the path containing the projects the auto grader will grade.
find $1 -name "*.txt" -exec sh -c "dirname {}"
When I try adding /somename.pdf to the end of this statement I get readme.txt/somename.pdf
along with another -exec to get the name for the file.
\; -exec sh -c "dirname {} xargs -n 1 basename" \;
I'm having problems combining these two into one working statement.
I'm new to unix programming and would appreciate any advice or help even if it means re-writing the code using different unix tools.
The main question here is how do I create files in a path other than the directory I call my script from. Thanks in advance.
How about this?
find "$1" -name "*.txt" -exec bash -c 'd=$(dirname "$1"); touch $d"/"$(basename "$d").pdf' - {} \;
You can create files in another path using change directory command (cd).
If you start your script in usr/autograder/script and want to change to usr/autograder/jdoe you can change directory with shell command cd ../jdoe (relative) or cd usr/autograder/jdoe (absolute).
Now you are in the directory of usr/autograder/jdoe and you are able to create files in this directory, for example gedit readme.txt will open gedit and creates the file in usr/autograder/jdoe.
The simplest way is to loop over the files returned by find and then do whatever you need to do.
For example:
find "$1" -type f -name "*.txt" -print0 | while IFS= read -r -d $'\0' filename; do
dir=$(dirname "$filename")
# create pdf file
touch "$dir/${dir##*/}.pdf"
done
(Note the use of find -print0 to correctly handle filenames containing whitespace and newline characters.)
Is this what you are looking for?
function process_file {
dir=$(dirname "$1")
name=$(basename "$1")
echo name is $name and dir is $dir;
cd "$dir"
touch "${dir##*/}.pdf" # or anything else
}
# export the function, so that it is known in the child processes
export -f process_file
find . -name '*.txt' -exec bash -c "process_file '{}'" \;
I would like to ensure that all files found by find with a given criteria are properly copied to the required location.
$from = '/some/path/to/the/files'
$ext = 'custom_file_extension'
$dest = '/new/destination/for/the/files/with/given/extension'
cp 'find $from -name "*.$ext"' $dest
The problem here is that, when a file found with the proper extension and it is containing space cp cannot copy it properly.
You don't do that. You can't splat filenames with spaces that way.
You either get to use something from http://mywiki.wooledge.org/BashFAQ/001 to read the output from find line-by-line or into an array or you use find -exec to do the copy work.
Something like this:
from='/some/path/to/the/files'
ext='custom_file_extension'
dest='/new/destination/for/the/files/with/given/extension'
find "$from" -name "*.$ext" -exec cp -t "$dest" {} +
Using -exec command + here means that find will only execute as many cp commands as it needs based on command length limits. Using -exec command ; here would run one cp-per-file-found (but is more portable to older systems).
See comment from gniourf_gniourf about the use of -t in that cp command to make -exec command + work correctly.
Use -exec:
find "$from" -name "*.$ext" -exec cp {} "$dest" \;
you need to copy file one by one:
for file in "$from"/*."$ext"; do
cp "$file" "$dest"
done
I just use glob here, and it's enough and complete. I think find may introduce problem if the file name contains funny character.
The solution for this sort of problem is xargs -0 and the -print0 flag for find.
-print0 instructs find to print the results with a NUL character termination, instead of a newline, while -0 for xargs tells it expect input in that format.
Finally, the -J option for xargs allows one to put the arguments in the right place for a copy.
find "$from" -name "*.$ext" -print0 | xargs -0 -J % cp % "$dest"
It's better to use -exec argument of find command to do this:
find . -type f -name "*.ext" -exec cp {} ./destination_dir \;
I've checked this case with files containing spaces and it's work for me. Also don't forger to point out '-type f' if you want to find only files, not directories.
It seems like I am unable to find a direct answer to this question.
I appreciate your help.
I'm trying to find all files with a specific name in a directory, read the last 1000 lines of the file and copy it in to a new file in the same directory. As an example:
Find all files names xyz.log in the current directory, copy the last 1000 lines to file abc.log (which doesn't exist).
I tried to use the following command with no luck:
find . -name "xyz.log" -execdir tail -1000 {} > abc.log \;
The problem I'm having is that for all the files in the current directory, they all write to abc.log in the CURRENT directory and not in the directory where xyz.log resides. Clearly the find with execdir is first executed and then the output is redirected to abc.log.
Can you guys suggest a way to fix this? I appreciate any information/help.
EDIT- I tried find . -name "xyz.log" -execdir sh -c "tail -1000 {} > abc.log" \; as suggested by some of the friends, but it gives me this error: sh: ./tail: No such file or directory error message. Do you guys have any idea what the problem is?
Luckily the solution to use -printf is working fine.
The simplest way is this:
find . -name "xyz.log" -execdir sh -c 'tail -1000 "{}" >abc.log' \;
A more flexible alternative is to first print out the commands and then execute them all with sh:
find . -name "xyz.log" -printf 'tail -1000 "%p" >"%h/abc.log"\n' | sh
You can remove the | sh from the end when you're trying it out/debugging.
There is a bug in some versions of findutils (4.2 and 4.3, though it was fixed in some 4.2.x and 4.3.x versions) that cause execdir arguments that contain {} to be prefixed with ./ (instead of the prefix being applied only to {} it is applied to the whole quoted string). To work around this you can use:
find . -name "xyz.log" -execdir sh -c 'tail -1000 "$1" >abc.log' sh {} \;
sh -c 'script' arg0 arg1 runs the sh script with arg0, arg1, etc. passed to it. By convention, arg0 is the name of the executable (here, "sh"). From the script you can access the arguments using $0 (corresponding to "sh"), $1 (corresponding to find's expansion of {}), etc.
The redirect isn't passed into execdir, so abc.log shows up in the directory you run the command in. -execdir also doesn't like embedded redirects. but you can workaround the problem by passing -execdir a shell command with a redirect embedded, like this:
find . -name "xyz.log" -execdir sh -c '/usr/bin/tail -1000 {} > abc.log' \;
Much credit to this blog post (not mine):
http://www.microhowto.info/howto/act_on_all_files_in_a_directory_tree_using_find.html
Edit
I put the full path to tail in the command (assuming it's in /usr/bin on your system), since sh may load a .profile with a PATH that differs from your current shell.
Here's another non-find (well, sorta - it still uses find but doesn't try to shoehorn find into doing the whole thing):
while read f
do
d=$(dirname "${f}")
tail -n 1000 "${f}" > "${d}/abc.log"
done < <(find . -type f -name xyz.log -print)
If I run this command:
sudo find . -name *.mp3
then I can get a listing of lots of mp3 files.
Now I want to do something with each mp3 file in a loop. For example, I could create a while loop, and inside assign the first file name to the variable file. Then I could do something with that file. Next I could assign the second file name to the variable file and do with that, etc.
How can I realize this using a linux shell command? Any help is appreciated, thanks!
For this, use the read builtin:
sudo find . -name *.mp3 |
while read filename
do
echo "$filename" # ... or any other command using $filename
done
Provided that your filenames don't use the newline (\n) character, this should work fine.
My favourites are
find . -name '*.mp3' -exec cmd {} \;
or
find . -name '*.mp3' -print0 | xargs -0 cmd
While Loop
As others have pointed out, you can frequently use a while read loop to read filenames line by line, it has the drawback of not allowing line-ends in filenames (who uses that?).
xargs vs. -exec cmd {} +
Summarizing the comments saying that -exec...+ is better, I prefer xargs because it is more versatile:
works with other commands than just find
allows 'batching' (grouping) in command lines, say xargs -n 10 (ten at a time)
allows parallellizing, say xargs -P4 (max 4 concurrent processes running at a time)
does privilige separation (such as in the OP's case, where he uses sudo find: using -exec would run all commands as the root user, whereas with xargs that isn't necessary:
sudo find -name '*.mp3' -print0 | sudo xargs -0 require_root.sh
sudo find -name '*.mp3' -print0 | xargs -0 nonroot.sh
in general, pipes are just more versatile (logging, sorting, remoting, caching, checking, parallelizing etc, you can do that)
How about using the -exec option to find?
find . -name '*.mp3' -exec mpg123 '{}' \;
That will call the command mpg123 for every file found, i.e. it will play all the files, in the order they are found.
for file in $(sudo find . -name *.mp3);
do
# do something with file
done
Once I am in the directory containing .mp3 files, I can play songs randomly using
mpg123 -Z *.mp3
But if I want to recursively search a directory and its subfolders for .mp3 files and play them randomly, I tried following command, but it does not work.
mpg123 -Z <(find /media -name *.mp3)
(find /media -name *.mp3), when executed gives all .mp3 files present in /media and its sub directories.
How can I get this to work?
mpg123 -Z $(find -name "*.mp3")
The $(...) means execute the command and paste the output here.
Also, to bypass the command-line length limit laalto mentioned, try:
mpg123 -Z $(find -name "*.mp3" | sort --random-sort| head -n 100)
EDIT: Sorry, try:
find -name "*.mp3" | sort --random-sort| head -n 100|xargs -d '\n' mpg123
That should cope with the spaces correctly, presuming you don't have filenames with embedded newlines.
It will semi-randomly permute your list of MP3s, then pick the first 100 of the random list, then pass those to mpg123.
In both zsh and bash 4.0,
mpg123 -Z **/*.mp3
(Bash users will probably need to shopt -s globstar first.)
Backticks.
mpg123 -Z `find /media -name \*.mp3`
Though if you have a lot of files, you may encounter command line length limitations.
Would something like this work?
find /media -name *.mp3 -print0 | xargs -0 mpg123 -Z
The following works fine.
find /media -name "*.mp3" | xargs -d '\n' -n10 mpg123 -Z.
By '-n' option we can provide no. of arguments for a single invocation of command.
Even after I close the terminal where i wrote this command, the songs continue to play as the process mpg123 becomes an orphan and continues to run.
devikasingh#Interest:~$ ps -e | grep mpg123
7239 ? 00:00:01 mpg123
ps -f 7239
UID PID PPID C STIME TTY STAT TIME CMD
1000 7239 1 0 15:21 ? S 0:01 mpg123 -Z /media/MUSIC & PIC/audio_for_you/For You.mp3 /media/MUSIC & PIC/audio_for_you/In My Place.mp3 /
Thanks for the suggestions, By using them I was able to create the following script:
#!/bin/bash song=$(zenity --width=360 --height=320 --title "Select Folder" --file-selection --directory $HOME) find "$song" -name "*.mp3" | sort --random-sort | head -n 100 | xargs -d '\n' mpg123
Probably its better to use xargs, but I use a while loop in bash on Red Hat.
find . -iname "*.mp3" -print | sort -R --random-source=/dev/urandom | while IFS= read -r filename; do play "$filename"; done
The only problem with it is that it is annoying to kill. To kill it, you must hold down Ctrl-C until the while loop is killed.
while...do...done loops through each field in the sort output.
IFS describes the field separators.
IFS= makes each line a single field.
read copies the current field into the filename variable.
The -r option removes backslash processing, which doesn't seem to be necessary on Linux.
play is a simple way of using sox for playback.
I found this one and IMHO, much cleaner than other solutions. I don't own the credits, they goes to site owner.
find $HOME/mp3s -iname '*.mp3' | mpg123 -Z -# -
Found on https://dannyman.toldme.com/2004/12/28/howto-mpg123-random-mp3s/
I just changed from name to iname as sometimes files can have extension in caps...
I tried almost all and when mpg123 is run througth a pipe it returns this error: "Can't get terminal attributes" and I cannot use terminal control keys.
The only way I found to play a list of files found with the command find and be able to use terminal control keys is this (I have directories and files with spaces):
find /media -type f -iname "*.mp3" > /tmp/mp3list
mpg123 -CZvv -# /tmp/mp3list
It looks that mpg123 use the space as separator if you use $(find /media -type f -iname "*.mp3") and in my case doesn't work because I have spaces in all directory's names and in almost all file's names.
This is a script (playmp3.sh) to only execute find when the file doesn't exist:
#!/bin/sh
if ! [ -f /tmp/mp3list ]; then
find /media -type f -iname "*.mp3" > /tmp/mp3list
fi
mpg123 -CZvv -# /tmp/mp3list
I have my library in a separate partition an in my root dir i have this small script that also plays randomly previous song, i have like 40 gb of music, so they almost never repeat.
# !/bin/sh
cd "/media/$USER/7789f483-c7bf-46bc-9293-e8e05dd62199/musik/"
mpg123 -Z */*/*.mp3;