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Full Discussion: Bash variable expansion
Top Forums Shell Programming and Scripting Bash variable expansion Post 302997736 by jcdole on Thursday 18th of May 2017 04:03:25 PM
Old 05-18-2017
Bash variable expansion

Hello.
The file /etc/fstab contains
Code:
UUID=957c3295-9944-1593-82e2-2b90dede4312 /                     ext4       noatime,discard,acl,user_xattr        1 1

I fill a variable
Code:
SOME_LINE=$( cat /etc/fstab | grep \/\..*ext4 | grep noatime,discard )

echo $SOME_LINE
Code:
UUID=957c3295-9944-1593-82e2-2b90dede4312 / ext4 noatime,discard,acl,user_xattr 1 1

echo ${SOME_LINE}
Code:
UUID=957c3295-9944-1593-82e2-2b90dede4312 / ext4 noatime,discard,acl,user_xattr 1 1

echo "$SOME_LINE"
Code:
UUID=957c3295-9944-1593-82e2-2b90dede4312 /                     ext4       noatime,discard,acl,user_xattr        1 1

I would like to know why The 3 outputs are not the same.

Thank you for helping.

Last edited by jcdole; 05-18-2017 at 06:51 PM..
 

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Prophet::Test(3pm)					User Contributed Perl Documentation					Prophet::Test(3pm)

   set_editor($code)
       Sets the subroutine that Prophet should use instead of "Prophet::CLI::Command::edit_text" (as this routine invokes an interactive editor)
       to $code.

   set_editor_script SCRIPT
       Sets the editor that Proc::InvokeEditor uses.

       This should be a non-interactive script found in t/scripts.

   import_extra($class, $args)
   in_gladiator($code)
       Run the given code using Devel::Gladiator.

   repo_path_for($username)
       Returns a path on disk for where $username's replica is stored.

   repo_uri_for($username)
       Returns a file:// URI for $USERNAME'S replica (with the correct replica type prefix).

   replica_uuid
       Returns the UUID of the test replica.

   database_uuid
       Returns the UUID of the test database.

   replica_last_rev
       Returns the sequence number of the last change in the test replica.

   as_user($username, $coderef)
       Run this code block as $username.  This routine sets up the %ENV hash so that when we go looking for a repository, we get the user's repo.

   replica_uuid_for($username)
       Returns the UUID of the given user's test replica.

   database_uuid_for($username)
       Returns the UUID of the given user's test database.

   ok_added_revisions( { CODE }, $numbers_of_new_revisions, $msg)
       Checks that the given code block adds the given number of changes to the test replica. $msg is optional and will be printed with the test
       if given.

   serialize_conflict($conflict_obj)
       Returns a simple, serialized version of a Prophet::Conflict object suitable for comparison in tests.

       The serialized version is a hash reference containing the following keys:
	   meta => { original_source_uuid => 'source_replica_uuid' }
	   records => { 'record_uuid' =>
			  { change_type => 'type',
			    props => { propchange_name => { source_old => 'old_val',
							    source_new => 'new_val',
							    target_old => 'target_val',
							  }
				     }
			  },
			'another_record_uuid' =>
			  { change_type => 'type',
			    props => { propchange_name => { source_old => 'old_val',
							    source_new => 'new_val',
							    target_old => 'target_val',
							  }
				     }
			  },
		      }

   serialize_changeset($changeset_obj)
       Returns a simple, serialized version of a Prophet::ChangeSet object suitable for comparison in tests (a hash).

   run_command($command, @args)
       Run the given command with (optionally) the given args using a new Prophet::CLI object. Returns the standard output of that command in
       scalar form or, in array context, the STDOUT in scalar form *and* the STDERR in scalar form.

       Examples:

	   run_command('create', '--type=Foo');

   load_record($type, $uuid)
       Loads and returns a record object for the record with the given type and uuid.

   as_alice CODE, as_bob CODE, as_charlie CODE, as_david CODE
       Runs CODE as alice, bob, charlie or david.

perl v5.10.1							    2009-09-02							Prophet::Test(3pm)
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