[ORIGINAL CREATION] tact and skill of VIM

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: read  ! shell_command                 // VIM read in the output of shell_command

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:1,$ ! shell_command                     // output the whole text as input to shell_command  and save the output of this shell_command to replace the original test
:0 ! date                                        // create a time stamp to the test

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:g//S/,/^/s*$/join    // join each paragraph to a single line.

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       matches                               equivalent ~
/d    digit                                     [0−9]
/D    non−digit                            [^0−9]
/x     hex digit                              [0−9a−fA−F]
/X    non−hex digit                     [^0−9a−fA−F]
/s    white space                         [       ]
/S    non−white characters        [^      ]
/l     lowercase alpha                  [a−z]
/L    non−lowercase alpha          [^a−z]
/u    uppercase alpha                 [A−Z]
/U    non−uppercase alpha        [^A−Z]