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Say I have a file /templates/apple and I want to

  1. put it in two different places and then
  2. remove the original.

So, /templates/apple will be copied to /templates/used AND /templates/inuse and then after that I’d like to remove the original.

Is cp the best way to do this, followed by rm? Or is there a better way?

I want to do it all in one line so I’m thinking it would look something like:

cp /templates/apple /templates/used | cp /templates/apple /templates/inuse | rm /templates/apple

Is this the correct syntax?

codeforester
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John Redyns
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6 Answers6

1011

You are using | (pipe) to direct the output of a command into another command. What you are looking for is && operator to execute the next command only if the previous one succeeded:

cp /templates/apple /templates/used && cp /templates/apple /templates/inuse && rm /templates/apple

Or 

cp /templates/apple /templates/used && mv /templates/apple /templates/inuse

To summarize (non-exhaustively) bash's command operators/separators:

  • | pipes (pipelines) the standard output (stdout) of one command into the standard input of another one. Note that stderr still goes into its default destination, whatever that happen to be.
  • |&pipes both stdout and stderr of one command into the standard input of another one. Very useful, available in bash version 4 and above.
  • && executes the right-hand command of && only if the previous one succeeded.
  • || executes the right-hand command of || only it the previous one failed.
  • ; executes the right-hand command of ; always regardless whether the previous command succeeded or failed. Unless set -e was previously invoked, which causes bash to fail on an error.
Maxim Egorushkin
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    Upvoted. Official documentation https://www.gnu.org/software/bash/manual/bash.html#Lists – flow2k Jul 02 '18 at 20:56
115

Why not cp to location 1, then mv to location 2. This takes care of "removing" the original.

And no, it's not the correct syntax. | is used to "pipe" output from one program and turn it into input for the next program. What you want is ;, which seperates multiple commands.

cp file1 file2 ; cp file1 file3 ; rm file1

If you require that the individual commands MUST succeed before the next can be started, then you'd use && instead:

cp file1 file2 && cp file1 file3 && rm file1

That way, if either of the cp commands fails, the rm will not run.

sactiw
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Marc B
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12

Note that cp A B; rm A is exactly mv A B. It'll be faster too, as you don't have to actually copy the bytes (assuming the destination is on the same filesystem), just rename the file. So you want cp A B; mv A C

glenn jackman
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9

Another option is typing Ctrl+V Ctrl+J at the end of each command.

Example (replace # with Ctrl+V Ctrl+J):

$ echo 1#
echo 2#
echo 3

Output: 

1
2
3

This will execute the commands regardless if previous ones failed.

Same as: echo 1; echo 2; echo 3

If you want to stop execution on failed commands, add && at the end of each line except the last one.

Example (replace # with Ctrl+V Ctrl+J):

$ echo 1 &&#
failed-command &&#
echo 2

Output:

1
failed-command: command not found

In zsh you can also use Alt+Enter or Esc+Enter instead of Ctrl+V Ctrl+J

Eyal Levin
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4

Using pipes seems weird to me. Anyway you should use the logical and Bash operator:

$ cp /templates/apple /templates/used && cp /templates/apple /templates/inuse && rm /templates/apples

If the cp commands fail, the rm will not be executed.

Or, you can make a more elaborated command line using a for loop and cmp.

Peter Mortensen
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Renaud
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3

Try this..

cp /templates/apple /templates/used && cp /templates/apple /templates/inuse && rm /templates/apple

Peter
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