Developing a Shell Script

Prerequisites

• A shell script has been added. For details, see Creating a Script.
• A host connection has been created. The host is used to execute shell scripts. For details, see Table 9.
• You have locked the script. Otherwise, you must click Lock so that you can develop the script. A script you create or import is locked by you by default. For details, see the lock function.

Procedure

1. Log in to the DataArts Studio console. Locate an instance and click Access. On the displayed page, locate a workspace and click DataArts Factory.
   Figure 1 DataArts Factory
   
2. In the left navigation pane of DataArts Factory, choose Data Development > Develop Script.
3. In the script directory list, double-click a script that you want to develop. The script development page is displayed.
4. In the upper part of the editor, select script properties. Table 1 describes the script properties.

   Table 1 Shell script properties

   Parameter	Description	Example
   Host Connection	Selects the host where a shell script is to be executed.	N/A
   Parameter	Parameter transferred to the Shell script when it is executed. Parameters are separated by spaces, for example, a b c. The parameter must be referenced by a location variable (for example, $1, $2, or $3) in the Shell script. Otherwise, the parameter is invalid. The location variable starts from 0. Variable 0 is reserved for storing the actual script name, variable 1 corresponds to the first parameter of the script, and so on. For example, $1, $2, and $3 reference parameters a, b, and c, respectively. Note: If a variable is referenced in the shell script, use the $args format instead of the ${args} format. Otherwise, the variable will be replaced by a parameter with the same name in the job.	For example, if you enter a b c and run the following Shell script, b is displayed: echo $2
   Interactive Input	Interactive information (for example, passwords) provided during shell script execution.	For example, run the following interactive Shell script. Interaction parameters 1, 2, and 3 correspond to begin, end, and exit, respectively. When the interaction parameter is set to 1, the execution result is start something. When the interaction parameter is set to 2, the execution result is stop something. When the interaction parameter is set to 3, the execution result is exit. #!/bin/bash select Actions in "begin" "end" "exit" do case $Actions in "begin") echo "start something" break ;; "end") echo "stop something" break ;; "exit") echo "exit" break ;; *) echo "Ignorant" ;; esac done

5. Edit shell statements in the editor. To facilitate script development, DataArts Factory provides the following capabilities:
   • The script editor supports the following shortcut keys, which improve the script development efficiency:
     • Ctrl + /: Comment out or uncomment the line or code block at the cursor.
     • Ctrl + S: Save
     • Ctrl +Z: Cancel
     • Ctrl + Y: Redo
     • Ctrl + F: Search
     • Ctrl + Shift + R: Replace
     • Ctrl + X: Cut (cut a line when the cursor selects nothing).
     • Alt + mouse dragging: Select columns to edit a block.
     • Ctrl + mouse click: Select multiple lines to edit or indent them together.
     • Shift + Ctrl + K: Delete the current line.
     • Ctrl + → (or ←): Move the cursor rightwards (or leftwards) by word.
     • Ctrl + Home or Ctrl + End: Navigate to the beginning or end of the current file.
     • Home or End: Navigate to the beginning or end of the current line.
     • Ctrl + Shift + L: Double-click all the same character strings and add cursors to them to implement batch modification.
   • Script parameter function. Use this function in either of the following ways:
     1. Write the script parameter name and parameter value in the shell statement. When the shell script is referenced by a job, if the parameter name configured for the job is the same as the parameter name of the shell script, the parameter value of the shell script is replaced by the parameter value of the job.

        An example is as follows:

        a=1
        echo ${a}

        In the preceding command, a indicates the parameter name. It can contain only letters, digits, hyphens (-), underscores (_), greater-than signs (>), and less-than signs (<), and can contain a maximum of 16 characters. The parameter name must be unique.

     2. Configure parameters in the upper part of the editor. When you execute the shell script, the configured parameters are transferred to the script. Separate parameters by spaces, for example, a b c. The parameter must be referenced by the shell script. Otherwise, the parameter is invalid.

        Note: If a variable is referenced in the shell script, use the $args format instead of the ${args} format. Otherwise, the variable will be replaced by a parameter with the same name in the job.

   • Owner

     Click Basic Info to set the script owner and description.

6. In the lower part of the editor, click Execute. After executing the shell statement, view the execution history and result of the script in the lower part of the editor.
   NOTE:

   You can perform the following operations on execution results:

   • Double-click or right-click the name of an execution result tab to rename it. The name can contain a maximum of 16 characters.
   • Right-click the name of an execution result tab to close the current tab, all the tabs to the left or right of the current tab, all the other tabs, or all the tabs.
7. Above the editor, click to save the script.
   If the script is created but not saved, set the parameters listed in Table 2.

   Table 2 Script parameters

   Parameter	Mandatory	Description
   Script Name	Yes	Name of the script. It contains a maximum of 128 characters. Only letters, digits, hyphens (-), underscores (_), and periods (.) are allowed.
   Description	No	Descriptive information about the script.
   Select Directory	Yes	Directory to which the script belongs. The root directory is selected by default.