A printer comprising: a printer unit (31, 71, 72, 73) capable of printing a bar code based on bar code data; an input unit that is configured to allow input operations; a data generator unit that is configured to generate an operation command string from a sequence of input operations by linking together operation commands each corresponding to an input operation through the input unit; a data recorder unit that is configured to record the operation command string generated by the data generator unit; and a bar-code-converter unit that is configured to convert the operation command string recorded by the data recorder unit into two-dimensional bar code data; wherein the printer unit (31, 71, 72, 73) is configured to print a bar code based on the two-dimensional bar code data created by the bar-code-converter unit; and wherein the printer further comprises: a reader unit (7, 61) that is configured to read the operation command string from the bar code printed by the printer unit (31, 71, 72, 73); an executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) that is configured to execute in order the operation commands of the operation command string read by the reader unit (7, 61); characterized in that the printer further comprises: a time setting unit that is configured to set an interval of time for executing each of the operation commands; wherein the executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) is configured to execute each of the operation commands at the interval of time set by the time setting unit. a printer unit (31, 71, 72, 73) capable of printing a bar code based on bar code data; an input unit that is configured to allow input operations; a data generator unit that is configured to generate an operation command string from a sequence of input operations by linking together operation commands each corresponding to an input operation through the input unit; a data recorder unit that is configured to record the operation command string generated by the data generator unit; and a bar-code-converter unit that is configured to convert the operation command string recorded by the data recorder unit into two-dimensional bar code data; wherein the printer unit (31, 71, 72, 73) is configured to print a bar code based on the two-dimensional bar code data created by the bar-code-converter unit; and wherein the printer further comprises: a reader unit (7, 61) that is configured to read the operation command string from the bar code printed by the printer unit (31, 71, 72, 73); an executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) that is configured to execute in order the operation commands of the operation command string read by the reader unit (7, 61); characterized in that the printer further comprises: a time setting unit that is configured to set an interval of time for executing each of the operation commands; wherein the executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) is configured to execute each of the operation commands at the interval of time set by the time setting unit. a reader unit (7, 61) that is configured to read the operation command string from the bar code printed by the printer unit (31, 71, 72, 73); an executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) that is configured to execute in order the operation commands of the operation command string read by the reader unit (7, 61); characterized in that the printer further comprises: a time setting unit that is configured to set an interval of time for executing each of the operation commands; wherein the executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) is configured to execute each of the operation commands at the interval of time set by the time setting unit. a time setting unit that is configured to set an interval of time for executing each of the operation commands; wherein the executor unit (61, 67, 27, 28, 31, 71, 72, 73, 74, 75) is configured to execute each of the operation commands at the interval of time set by the time setting unit.