Copy directory tree with cp

idempotent-cp-tree-test-1.sh

#!/bin/bash
set -eu

# this script is meant to be run on macos with gnu cp avalable via gcp (brew install coreutils)
# and macs own cp as cp  

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

cd "$SCRIPT_DIR"


# By default cp -R of directory tree's are not idempotent, so that the second cp does not update the previous one but is copied into an existin directory.

# Lets first create some testdir to be copied in folder 'stuff'
rm -rf stuff
mkdir -p stuff/nm
touch stuff/a
touch stuff/.c
touch stuff/nm/p
touch stuff/nm/.c2

# TODO 
# cp -r stuff tdir/tname did no work
# First showcase the problem

init() {
    echo "test with $1"
    clean_expected_actual
    rm -rf tdir && mkdir tdir # this must exist for both gcp and cp
}

clean_expected_actual() {
rm -rf expected && mkdir expected
rm -rf actual && mkdir actual
}

check_results_tdir_tname() {
# -- check results
find tdir/tname > actual/tname
cat << EOF > expected/tname
tdir/tname
tdir/tname/a
tdir/tname/.c
tdir/tname/nm
tdir/tname/nm/.c2
tdir/tname/nm/p
EOF
diff expected/tname actual/tname
}

check_confused_results() {
# -- check results
find tdir/tname > actual/tname-1
cat << EOF > expected/tname-1
tdir/tname
tdir/tname/a
tdir/tname/stuff
tdir/tname/stuff/a
tdir/tname/stuff/.c
tdir/tname/stuff/nm
tdir/tname/stuff/nm/.c2
tdir/tname/stuff/nm/p
tdir/tname/.c
tdir/tname/nm
tdir/tname/nm/.c2
tdir/tname/nm/p
EOF
diff expected/tname-1 actual/tname-1
}

check_results_tdir_tname_stuff() {
find tdir/tname > actual/tname
cat << EOF > expected/tname
tdir/tname
tdir/tname/stuff
tdir/tname/stuff/a
tdir/tname/stuff/.c
tdir/tname/stuff/nm
tdir/tname/stuff/nm/.c2
tdir/tname/stuff/nm/p
EOF
diff expected/tname actual/tname
}


# -- 'naive' cp command 
init "'naive' cp command"
cp -r stuff tdir/tname
check_results_tdir_tname

cp -r stuff tdir/tname
check_confused_results

# -- 'naive' cp command when tdir/tname exists
init "'naive' cp command when tdir/tname exists"
mkdir tdir/tname
cp -r stuff tdir/tname
check_results_tdir_tname_stuff

cp -r stuff tdir/tname
check_results_tdir_tname_stuff

# -- 'naive' gnu gcp command 
init "same with gcp"

gcp -r stuff tdir/tname
check_results_tdir_tname

gcp -r stuff tdir/tname
check_confused_results

# -- 'naive' gnu gcp command when tdir/tname exists
init "'naive' gnu gcp command when tdir/tname exists"
mkdir tdir/tname
gcp -r stuff tdir/tname
check_results_tdir_tname_stuff

gcp -r stuff tdir/tname
check_results_tdir_tname_stuff

# -- gcp using --no-target-directory
init "gcp using --no-target-directory"

gcp --no-target-directory -r stuff tdir/tname
check_results_tdir_tname

gcp --no-target-directory -r stuff tdir/tname
check_results_tdir_tname

# -- gcp using --no-target-directory with explicit stuff
init "gcp using --no-target-directory with explicit stuff"
mkdir tdir/tname
gcp --no-target-directory -r stuff tdir/tname/stuff
check_results_tdir_tname_stuff

gcp --no-target-directory -r stuff tdir/tname/stuff
check_results_tdir_tname_stuff

# -- gcp using --target-directory
init "gcp using --target-directory"
echo "must create target directory first otherwise fails"
mkdir tdir/tname  
gcp --target-directory=tdir/tname -r stuff 
# results reflect that the stuff name is kept:
check_results_tdir_tname_stuff
gcp --target-directory=tdir/tname -r stuff 
check_results_tdir_tname_stuff

# -- gcp using cmd suggested on sov
init "gcp using cmd suggested on sov"

gcp -r stuff/. tdir/tname
check_results_tdir_tname

gcp -r stuff/. tdir/tname
check_results_tdir_tname

# -- bsd cp using cmd suggested on sov
init "bsd cp using cmd suggested on sov"

cp -r stuff/. tdir/tname
check_results_tdir_tname

cp -r stuff/. tdir/tname
check_results_tdir_tname

idempotent-cp-tree-test-2.sh

#!/bin/bash
set -eu

# this script is meant to be run on macos with gnu cp avalable via gcp (brew install coreutils)
# and macs own cp as cp  

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

cd "$SCRIPT_DIR"


# By default cp -R of directory tree's are not idempotent, so that the second cp does not update the previous one but is copied into an existin directory.

# Lets first create some testdir to be copied in folder 'stuff'
rm -rf stuff
mkdir -p stuff/nm
touch stuff/a
touch stuff/.c
touch stuff/nm/p
touch stuff/nm/.c2

init() {
    echo "test with $1"
    clean_expected_actual
    rm -rf tdir && mkdir tdir # this must exist for both gcp and cp
}

clean_expected_actual() {
rm -rf expected && mkdir expected
rm -rf actual && mkdir actual
}

check_results_tdir_stuff() {
# -- check results
find tdir > actual/tname
cat << EOF > expected/tname
tdir
tdir/stuff
tdir/stuff/a
tdir/stuff/.c
tdir/stuff/nm
tdir/stuff/nm/.c2
tdir/stuff/nm/p
EOF
diff expected/tname actual/tname
}

check_results_tdir() {
find tdir > actual/tname
cat << EOF > expected/tname
tdir
tdir/a
tdir/.c
tdir/nm
tdir/nm/.c2
tdir/nm/p
EOF
diff expected/tname actual/tname
}

# -- test 'naive' cp command 
init "'naive' cp command"
cp -r stuff tdir
check_results_tdir_stuff
cp -r stuff tdir
check_results_tdir_stuff

# -- same with gcp 
init "same with gcp"

gcp -r stuff tdir
check_results_tdir_stuff

gcp -r stuff tdir
check_results_tdir_stuff

# -- gcp using --no-target-directory
init "gcp using --no-target-directory"

gcp --no-target-directory -r stuff tdir
check_results_tdir

gcp --no-target-directory -r stuff tdir
check_results_tdir

# -- gcp using --target-directory
init "gcp using --target-directory"
gcp --target-directory=tdir -r stuff 
# results reflect that the stuff name is kept:
check_results_tdir_stuff
gcp --target-directory=tdir -r stuff 
check_results_tdir_stuff

# -- gcp using cmd suggested on sov
init "gcp using cmd suggested on sov"

gcp -r stuff/. tdir
check_results_tdir

gcp -r stuff/. tdir
check_results_tdir

# -- bsd cp using cmd suggested on sov
init "bsd cp using cmd suggested on sov"

cp -r stuff/. tdir
check_results_tdir

cp -r stuff/. tdir
check_results_tdir

The above scripts are meant to reduce confusion about how the cp command works when it copies directory trees.

Some related links:

• How to copy a folder recursively in an idempotent way using cp?
• Section about special options in gnu cp Target directory (GNU Coreutils 9.0)
• cp This is likely similar to the cp command in macos, but I did not find an online developer guide for the latest version. So you may want to compare to man cp