Implement false, true, and whatis

Fixes #129. Fixes #131.

package.json

@@ -1,6 +1,6 @@
 {
     "name": "fwdekker.com",
-    "version": "0.35.0",
+    "version": "0.36.0",
     "description": "The source code of [my personal website](https://fwdekker.com/).",
     "author": "Felix W. Dekker",
     "browser": "dist/bundle.js",

src/main/js/Commands.ts

@@ -507,6 +507,14 @@ return new Command(
     \`exit\`,
     \`Closes the terminal session.\`,
     new InputValidator({maxArgs: 0})
+)`,
+    "false": /* language=JavaScript */ `\
+return new Command(
+    () => {return ExitCode.MISC;},
+    \`return unsuccessful exit code\`,
+    \`false\`,
+    \`Set the <tt>status</tt> environment variable to ${ExitCode.MISC}.\`.trimMultiLines(),
+    new InputValidator({minArgs: 0})
 )`,
     "help": /* language=JavaScript */ `\
 return new Command(
@@ -519,8 +527,8 @@ return new Command(
 
                     const command = josh.interpreter.resolve(commandName);
                     if (command === undefined) {
-                        streams.out.writeLine(\`Unknown command '\${commandName}'.\`);
-                        return ExitCode.COMMAND_NOT_FOUND;
+                        streams.err.writeLine(\`help: Unknown command '\${commandName}'.\`);
+                        return ExitCode.USAGE;
                     }
 
                     let helpString = "<b>Name</b>\\n" + commandName;
@@ -945,6 +953,14 @@ return new Command(
     \`Update the access and modification times of each <u>file</u> to the current time. If a <u>file</u> does not ${n}
     exist, it is created.\`.trimMultiLines(),
     new InputValidator({minArgs: 1})
+)`,
+    "true": /* language=JavaScript */ `\
+return new Command(
+    () => {return ExitCode.OK;},
+    \`return successful exit code\`,
+    \`true\`,
+    \`Set the <tt>status</tt> environment variable to ${ExitCode.OK}.\`.trimMultiLines(),
+    new InputValidator({minArgs: 0})
 )`,
     "useradd": /* language=JavaScript */ `\
 return new Command(
@@ -1049,6 +1065,27 @@ return new Command(
     \`Modifies the user with the given <u>name</u>. See the "useradd" command for more information on the fields ${n}
     that can be modified.\`.trimMultiLines(),
     new InputValidator({minArgs: 1, maxArgs: 1})
+)`,
+    "whatis": /* language=JavaScript */ `\
+return new Command(
+    (input, streams) => {
+        return input.args
+            .map(commandName => {
+                const command = josh.interpreter.resolve(commandName);
+                if (command === undefined) {
+                    streams.err.writeLine(\`whatis: Unknown command '\${commandName}'.\`);
+                    return ExitCode.USAGE;
+                }
+
+                streams.out.writeLine("<b>" + commandName + "</b> - " + command.summary);
+                return ExitCode.OK;
+            })
+            .reduce((acc, exitCode) => exitCode === ExitCode.OK ? acc : exitCode);
+    },
+    \`display one-line documentation\`,
+    \`whatis <u>command</u> <u>...</u>\`,
+    \`Displays a one-line summary for each <u>command</u>.\`.trimMultiLines(),
+    new InputValidator({minArgs: 1})
 )`,
     "whoami": /* language=JavaScript */ `\
 return new Command(

src/test/Commands.spec.ts

@@ -324,11 +324,25 @@ describe("commands", () => {
             });
         });
 
+        describe("false", () => {
+            beforeEach(() => loadCommand("false"));
+
+
+            it("sets the exit code to an erroneous value", () => {
+                expect(execute("false")).to.not.equal(ExitCode.OK);
+            });
+        });
+
         describe("help", () => {
             beforeEach(() => loadCommand("help"));
 
 
-            it("outputs something", () => {
+            it("outputs an error if the command could not be found", () => {
+                expect(execute("help error")).to.equal(ExitCode.USAGE);
+                expect(readErr()).to.equal("help: Unknown command 'error'.\n");
+            });
+
+            it("outputs something if the command could be found", () => {
                 expect(execute("help help")).to.equal(ExitCode.OK);
                 expect(readOut()).to.not.equal("");
             });
@@ -722,6 +736,15 @@ describe("commands", () => {
             });
         });
 
+        describe("true", () => {
+            beforeEach(() => loadCommand("true"));
+
+
+            it("sets the exit code to a successful value", () => {
+                expect(execute("true")).to.equal(ExitCode.OK);
+            });
+        });
+
         describe("useradd", () => {
             before(() => HashProvider.default = plainHashProvider);
 
@@ -834,6 +857,21 @@ describe("commands", () => {
             });
         });
 
+        describe("whatis", () => {
+            beforeEach(() => loadCommand("whatis"));
+
+
+            it("outputs an error if a command could not be found", () => {
+                expect(execute("whatis error")).to.equal(ExitCode.USAGE);
+                expect(readErr()).to.equal("whatis: Unknown command 'error'.\n");
+            });
+
+            it("outputs a short summary of itself", () => {
+                expect(execute("whatis whatis")).to.equal(ExitCode.OK);
+                expect(readOut()).to.equal("<b>whatis</b> - display one-line documentation\n");
+            });
+        });
+
         describe("whoami", () => {
             beforeEach(() => loadCommand("whoami"));