Confusion on the cp command when creating a new directory

cpdirectory

Let me explain my problem with a simpler scenario. We have these two directories: ~/Foo and ~/Bar. Foo contains the files test1.txt and test2.txt. If I run the command cp -R Foo Bar, the Bar directory now contains a Foo folder containing the two text files. However, if I run the command cp -R Foo Bar when the Bar directory does not yet exist before the command is run, the newly created Bar directory will not contain a Foo subdirectory but only the two .txt files.

Why is it when I run the command in the first situation that it creates a subdirectory with the two files but in the second situation it just copies the two files into the new directory? Is the cp program supposed to function in this way?

Best Answer

The command cp Foo Bar says "Copy the Foo directory to Bar". If it already exists, it will put Foo inside of Bar. If you want explicitly to copy the contents of Foo, use cp -r Foo/ Bar/ or, better, use rsync -a. To elaborate: if Bar does not exist, it will be created wtih cp; if it does not, it will act as the destination into which you want to copy files.

Related Solutions

Shell – Make Directory Copies Using Find Command

This is not a job for find, since there is no recursion involved.

for x in */C/populate.sh; do
  mkdir -- "${x%%/*}$suffix"
  mkdir -- "${x%%/*}$suffix/C"
  cp -p -- "$x" "./${x%%/*}$suffix/C"
done

Remove the -p option to cp if you don't want to preserve the files' modification time.

To generate a random suffix, BSD/Linux mktemp is as portable as it gets.

suffix=$(mktemp -u tmp_XXXXX)

If you want something vaguely random-looking and POSIX-compliant, this gives a string that changes every second and varies from location to location; you can't really do better with only POSIX tools:

suffix=$({ hostname; pwd; date; } |
         cksum | uuencode -m /dev/stdin | awk 'NR==2 {print substr($0,3,5)}')

If you put this code in a makefile, remember to:

double all $ signs;
put all the code on one line, using ; instead to separate shell instructions (you can use backslash+newline+tab to put a line break in the makefile, but that sequence is removed to build the shell command);
start the shell snippet with set -e, so that it aborts if there is any error.

Unzip file contents, but without creating archive folder

My version of unzip has a -j option to not create any directory.

unzip -j /path/to/file.zip

Will extract all the files into the current directory without restoring the directory structure stored in the zip file.

If you want to only remove one level of directories from the archive, (extract myarchive/dir/file as dir/file, not file), you could use bsdtar (which does supports zip files in addition to tar files) instead and its -s option.

bsdtar -xf /path/to/file.zip -s'|[^/]*/||'

Best Answer

Related Solutions

Shell – Make Directory Copies Using Find Command

Unzip file contents, but without creating archive folder

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