Why can't I create a directory by full relative path argument?

Question

Why can't I create a directory by full relative path argument? Here is what I try:

#!/bin/bash
args=("$@")
# Print the command and run it. Exit the script on failure.
run()
{
        if $VERBOSE; then
                echo "$@"
                "$@"
        else
                "$@" >& /dev/null
        fi
        result=$?
        if [ $result -ne 0 ]; then
                exit $result
        fi
}
                if [ ! -d ${args[0]} ]; then
                        run mkdir -p ${args[0]}
                fi

                run cd ./release/
                run cp -rf ./html/ ${args[0]}

but I get:

mkdir -p ./bla/bla/cloud/
cd ./release/
cp -rf ./html/ ./bla/bla/cloud/
cp: cannot create directory `./bla/bla/cloud/': No such file or directory

So I wonder how to make script work when called like this: ./script.sh ./bla/bla/bla/

Answer 1

Suppose you start from /some/dir.

mkdir -p ./bla/bla/cloud/          # create /some/dir/bla/bla/cloud
cd ./release/                      # cd /some/dir/release
cp -rf ./html/ ./bla/bla/cloud/    # copy to /some/dir/release/bla/bla/cloud

By definition, a relative path changes when you change the current directory.

Answer 2

The issue is you are using relative paths but you change directories in the middle of the script. If you mentally trace through the steps:

# command                     # relevant absolute path(s)
./script.sh ./bla/bla/bla/    # PWD/script.sh 
mkdir -p ./bla/bla/bla/       # PWD/bla/bla/bla/
cd ./release/                 # PWD/release
cp -rf ./html/ ./bla/bla/bla/ # PWD/release/html PWD/release/bla/bla/bla   

Notice how you created PWD/bla/bla/bla/ but are attempting to copy into PWD/release/bla/bla/bla/. You should make sure the mkdir and the cp occur in the same directory.

---

Here's a suggested alternative. I replaced the entire run () function with the shell options xtrace (-x), which displays every command before it is run, and errexit (-e), which exits if any command returns an error.

#!/bin/bash -xe

cd ./release/

if [ ! -d "$1" ]; then
        mkdir -p "$1"
fi
cp -rf ./html "$1"