How to check progress of running cp?

Question

Is it possible to check the progress of running cp process? Some processes respond to various KILL signals so that you can check what is their status. I know that I can run cp with parameter -v but what if forgot to do that, cp is running for a very long time and I want to know which file is being copied, or how many were already copied.

Answer 1

On recent versions of Mac OS X you can just hit CTRL+T to see progress. From the OSX 10.6 man page for cp(1):

 "If cp receives a SIGINFO (see the status argument for stty(1)) signal,
 the current input and output file and the percentage complete will be
 written to the standard output."

Hitting CTRL+T is equivalent to signaling the current process with SIGINFO on BSD-ish machines, including OSX.

This works for dd(1) as well.

I don't think Linux has this SIGINFO mechanism, and don't see anything in the GNU man page for cp(1) about signals that can be used to report progress.

Answer 2

Yes, by running stat on target file and local file, and get a file size,

i.e stat -c "%s" /bin/ls

And you get the percentage of data copied by comparing the two value, that's it

In a very basic implementation that will look like this:

function cpstat()
{
  local pid="${1:-$(pgrep -xn cp)}" src dst
  [[ "$pid" ]] || return
  while [[ -f "/proc/$pid/fd/3" ]]; do
    read src dst < <(stat -L --printf '%s ' "/proc/$pid/fd/"{3,4})
    (( src )) || break
    printf 'cp %d%%\r' $((dst*100/src))
    sleep 1
  done
  echo
}

Answer 3

When you're copying a lot of files, du -s /path/to/destination or find /path/to/destination | wc -l gives you an idea of how much has already been done.

You can find out which file is being copied with lsof -p1234 where 1234 is the process ID of cp. Under many systems, pgrep -x cp reports the process IDs of all running processes named cp. This may not be very useful as the order in which the files inside a given directory are copied is essentially unpredictable (in a large directory under Linux, ls --sort=none will tell you; with a directory tree, try find).

lsof -p1234 also tells you how many bytes cp has already read and written for the current file, in the OFFSET column.

Under Linux, there are IO usage statistics in /proc/$pid/io (again, use the PID of the cp process for $pidf). The rchar value is the total number of bytes that the process has read, and wchar is the number of bytes that the process has written. This includes not only data in files but also metadata in directories. You can compare that figure with the approximate figure obtained with du /path/to/source (which only counts file data). read_bytes and write_bytes only include what has been read or written from storage, i.e. it excludes terminal diagnostics and data already in cache or still in buffers.

Answer 4

A relatively new tool that does exactly that is progress (formerly cv [coreutils viewer]).

What is it?

This tool can be described as a Tiny, Dirty, Linux-and-OSX-Only C command that looks for coreutils basic commands (cp, mv, dd, tar, gzip/gunzip, cat, etc.) currently running on your system and displays the percentage of copied data.

How does it work?

It simply scans /proc for interesting commands, and then looks at directories fd and fdinfo to find opened files and seek positions, and reports status for the largest file.

Answer 5

One of my favorite tricks for this (under Linux) is to find out the PID of the cp process (using ps | grep cp or similar), and then to look in /proc/$PID/fd/ and /proc/$PID/fdinfo/.

$ cp -r y z
^Z
$ ls -l /proc/8614/fd
lrwx------ 1 jander jander 64 Aug  2 15:21 0 -> /dev/pts/4
lrwx------ 1 jander jander 64 Aug  2 15:21 1 -> /dev/pts/4
lrwx------ 1 jander jander 64 Aug  2 15:20 2 -> /dev/pts/4
lr-x------ 1 jander jander 64 Aug  2 15:21 3 -> /home/jander/y/foo.tgz
l-wx------ 1 jander jander 64 Aug  2 15:21 4 -> /home/jander/z/foo.tgz

This will show you what files the process has open. If you want to see how far into the file the process is...

$ cat /proc/8614/fdinfo/3
pos:    105381888
flags:  0500000

the pos parameter is the position of the read (or write) pointer, in bytes.

Answer 6

While the OP has specifically mentioned the ability to see how the "cp" command is progressing, it must be said that other utilities are better for this particular issue.

For example:

rsync -avP FROM TO

will show the progress of copying the FROM file/folder to the TO file/FOLDER.

---

# rsync -avP Video.mp4  /run/media/user1/3.8G/

sending incremental file list
Video.mp4
    565,170,046 100%   51.23MB/s    0:00:10 (xfr#1, to-chk=0/1)

sent 565,308,115 bytes  received 134 bytes  5,210,214.28 bytes/sec
total size is 565,170,046  speedup is 1.00

---

And rsync will tell you how much it's copied (and the transfer rate) along the way. It works for single files or folder both on the same machine or across the network.

Answer 7

There are a few things you can do. You could attach strace to it to see what it's doing (output may be copious!):

strace -p [pid of cp]

or you could get lsof to tell you which files it currently has open:

lsof -p [pid of cp]

If you're running a big recursive cp, you could use pwdx to get the current working directory, which may give you some idea of how it's doing:

pwdx [pid of cp]

Answer 8

I would like to add cpv, a little wrapper for pv that I wrote that imitates the usage of cp.

Simple and useful

You can get it here

Answer 9

This tool is a Linux utility command that looks for coreutils basic commands (cp, mv, dd, tar, gzip/gunzip, cat, etc.) currently running on your system and displays the percentage of copied data:

https://github.com/Xfennec/cv

Answer 10

Use pv -d:

-d PID[:FD], --watchfd PID[:FD]
Instead of transferring data, watch file descriptor FD of process PID, and show its progress. […] If only a PID is specified, then that process will be watched, and all regular files and block devices it opens will be shown with a progress bar. The pv process will exit when process PID exits.

^(source)

Find out the PID of your running cp (pidof cp), let's say it's 12345; then simply

pv -d 12345

Notes:

• Run pv as the same user who runs cp (or as root).
• Since copying means reading one file and writing to the other, expect to see two files being monitored at a time.
• If cp is processing small files at the moment, you will probably not see all of them in the output (a small file may get closed too fast for pv to pick it up). Yet some will appear, so even then you will be able to tell what cp does.
• pv -d "$(pidof cp)" may work; but if there's more than one cp running, it won't work. There is pidof -s which returns at most one PID, but you cannot be sure it will belong to the right cp process if there are many.

Answer 11

You can get a realtime output of the lsof command referenced in the answer by @gilles by using watch like this:

watch -n1 lsof -p$(pgrep -x cp)

The -n1 flag sets the update interval to 1 second but you can set it to something lower like 0.5 for more accuracy. The default is 2 seconds.

You can also run the watch command with cp by using an ampersand &. For example, to copy somefile to /someplace, you can do this:

cp somefile /someplace & watch lsof -n1 -p$(pgrep -x cp)

Answer 12

What you can do is check the files at destination.

If your cp commands is something like cp -a <my_source> <my_dest_folder> I would check which files are already copied in <my_dest_folder> and each file size, so I can see the progress. If the <my_source> is a bit complex (several layers of directories) then a small script would be able to check the status. Although such a script could consume a bit of I/O that would then not be used by the cp process.

Answer 13

You may also use pipeviewer.

for f in *; do
  pv $f > destination/$f
done

Answer 14

@nachoparker provided a modern way of doing it. If you work on servers and don't have time to implement external things: use cp --verbose.

Answer 15

If there are any edge cases like mine who need to display the progress in a GUI, the accepted answer can be adapted to zenity pretty easily.

function cpstat_zenity()
{
  local pid="${1:-$(pgrep -xn cp)}" src dst
  [[ "$pid" ]] || return
  while [[ -f "/proc/$pid/fd/3" ]]; do
    # ignore nuisance stderr messages with 2> /dev/null
    read -r src dst < <(stat -L --printf '%s ' "/proc/$pid/fd/"{3,4} 2> /dev/null)
    (( src )) || break
    # print only an integer for zenity.
    # src + 1 keeps the bar from auto-closing if running on a loop.
    printf '%d\r' $((dst*100/src + 1))
    sleep 0.5
  done
}
cpstat_zenity | zenity  --width=300 --progress --auto-close

This can be put in an executable sh script and run straight from the file manager.

This also can be used purposefully like cp src dst & cpstat_zenity | zenity ... and also more complex loops.

function cp_loop()
{
    for file in /some/dir/*.iso; do
        echo "#Copying ${file}..."   # this displays in zenity
        cp "$file" /some/other/dir/ & cpstat_zenity
    done
}
cp_loop | zenity --progress --auto-close --width=300

Answer 16

You can send a signal to the process:

kill -SIGUSR1 pid

It is even more useful to create a script that polls until you press Ctrl-C or the process finished:

while [ : ] ; do kill -SIGUSR1 $1 && sleep 1m || exit ; done

Works for dd. Doesn't work for cp. Maybe you have to use another signal. I once tried SIGINFO, but it doesn't seem to exist any more on the Intel platform.