Shell Programming and Scripting

I like organising some of my folders in the format of yyyymmdd to keep them in chronological order.
For example, today which is 5th July 2014, I made a folder named 20140705.
I want to manipulate these folders from a shell script, but I cannot find out how to do it without typing the literal name of the folder, such as the following command.

Code:

mv 20140705 sommelier

This is not what I want to do because when I make a new folder in the future, I can't use the same script without modifying it.
I know that the date command can create a formatted output of today's date,

Code:

date +"20%y%m%d"

which will essentially give me the name of my folder I created today and will also work the same way in the future.
I tried using the output of this command to move today's folder to somedir, for example by using a pipe "|", but it didn't work.
Is there a simple way how to do what I want to do, or am I doing something that cannot be done by shell script?

You didn't say what shell you're using. With any shell that conforms to the POSIX standards, try:

Code:

mv $(date +"%Y%m%d") somedir

You should post the code you have tried so we can see what you are doing wrong.

This will do what you have described.

Code:

mv `date +"%Y%m%d"` sommelier

Dear Don, mjf

Both seems to work, thank you.
Somehow the missing "Code:" is also fixed without me doing anything, thank you for this as well.
Next time I will remember to mention that I am using bash when I ask questions.

Both are working, but you should use Dons suggestion in favour of mjfs: there is a mechanism called "process substitution" in bourne-like shells (Bourne-Shell, bash and ksh, to name the most popular ones). It does the following: take a command, run it in a subshell, then use the output of this command in the current commandline:

Code:

mv $(date +'.....') somewhere

This first runs date +'.....', which will display a string, say "20140102". This string now replaces the the command it comes from on the command line, so effectively:

Code:

mv 20140102 somewhere

is executed. So far, this is equally the case for both constructs:

Code:

mv $(date +'.....') somewhere
mv `date +'.....'` somewhere

The difference is, that the latter is the historic form, which is only supported for backwards compatibility. The modern - and POSIX-standardised - form to write this is the first. The modern form also has some subtle advantages, like the ability to be nested:

Code:

mv $(command1 | command2 $(command3) ) somewhere

This could not be written using backticks at all.

I hope this helps.

bakunin

/PS:

This is because Don Cragun edited them into your post, as you can see at the bottom of your post if you scroll up.

bakunin

Dear Bakunin,

This is also something useful to know.
Thank you.