feat(examples): add shell-like experience to advanced console example

Add Unix-like shell functionality to demonstrate console capabilities:
- Implement tee, cat, echo, and other shell commands
- Add esp_shell component for shell command execution
- Enable task-based command execution for pipelines
- Demonstrate pipe usage and I/O redirection

Shows practical usage of console task API and VFS pipe features.

Author: jimmyw

examples/system/console/advanced/components/cmd_system/CMakeLists.txt

@@ -1,4 +1,4 @@
-idf_component_register(SRCS "cmd_system.c" "cmd_system_common.c"
+idf_component_register(SRCS "cmd_system.c" "cmd_system_common.c" "cmd_system_shell_common.c"
                     INCLUDE_DIRS .
                     REQUIRES console spi_flash esp_driver_uart esp_driver_gpio)
 

examples/system/console/advanced/components/cmd_system/cmd_system.h

@@ -22,6 +22,14 @@ void register_system_common(void);
 void register_system_deep_sleep(void);
 void register_system_light_sleep(void);
 
+// Register common tools used in shell: cat, echo, grep, tail, tee
+void register_system_shell_common(void);
+
+void register_system_shell_tee(void);
+void register_system_shell_cat(void);
+void register_system_shell_grep(void);
+void register_system_shell_echo(void);
+
 #ifdef __cplusplus
 }
 #endif

examples/system/console/advanced/components/cmd_system/cmd_system_shell_common.c

@@ -0,0 +1,370 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Unlicense OR CC0-1.0
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <sys/stat.h>
+
+#include <inttypes.h>
+#include "esp_console.h"
+#include "argtable3/argtable3.h"
+#include "freertos/task.h"
+#include "cmd_system.h"
+
+static struct {
+    struct arg_str *path;
+    struct arg_lit *append;
+    struct arg_end *end;
+} tee_args;
+
+
+static int cmd_tee(int argc, char **argv)
+{
+    int nerrors = arg_parse(argc, argv, (void **)&tee_args);
+    if (nerrors != 0) {
+        arg_print_errors(stderr, tee_args.end, argv[0]);
+        return 1;
+    }
+
+    if (tee_args.path->count != 1) {
+        fprintf(stderr, "Please provide a single file path\n");
+        return 1;
+    }
+
+    const char *path = tee_args.path->sval[0];
+    const char *mode = (tee_args.append->count > 0) ? "a" : "w";
+
+    FILE *file = fopen(path, mode);
+    if (!file) {
+        fprintf(stderr, "tee: %s: %s\n", path, strerror(errno));
+        return 1;
+    }
+
+    char buf[256];
+    while (fgets(buf, sizeof(buf), stdin)) {
+        // Write to stdout
+        fputs(buf, stdout);
+        fflush(stdout);
+
+        // Write to file
+        fputs(buf, file);
+    }
+
+    fclose(file);
+    return 0;
+}
+
+void register_system_shell_tee(void) {
+    tee_args.path = arg_str1(NULL, NULL, "<path>", "File to write to");
+    tee_args.append = arg_lit0("a", "append", "Append to file instead of overwriting");
+    tee_args.end = arg_end(2);
+    const esp_console_cmd_t tee_cmd = {
+        .command = "tee",
+        .help = "Read from stdin and write to file and stdout",
+        .hint = NULL,
+        .func = &cmd_tee,
+        .argtable = &tee_args,
+    };
+    ESP_ERROR_CHECK(esp_console_cmd_register(&tee_cmd));
+}
+
+
+static struct {
+    struct arg_str *path;
+    struct arg_end *end;
+} cat_args;
+
+int cmd_cat(int argc, char **argv)
+{
+    int nerrors = arg_parse(argc, argv, (void **)&cat_args);
+    if (nerrors != 0) {
+        arg_print_errors(stderr, cat_args.end, argv[0]);
+        return 1;
+    }
+
+    if (cat_args.path->count != 1) {
+        fprintf(stderr, "Please provide a single file path\n");
+        return 1;
+    }
+    const char *path = cat_args.path->sval[0];
+
+    FILE *file = fopen(path, "r");
+    if (!file) {
+        fprintf(stderr, "File %s not found\n", path);
+        return 2;
+    }
+
+    while (true) {
+        char buf[32];
+        size_t bytes = fread(buf, 1, sizeof(buf), file);
+        if (bytes < 1)
+            break;
+        fwrite(buf, 1, bytes, stdout);
+    }
+
+    if (file) {
+        fclose(file);
+    }
+
+    return 0;
+}
+
+void register_system_shell_cat(void) {
+    cat_args.path = arg_str1(NULL, NULL, "<path>", "File to cat");
+    cat_args.end = arg_end(2);
+    const esp_console_cmd_t cat_cmd = {.command = "cat", .help = "cat file", .hint = NULL, .func = &cmd_cat, .argtable = &cat_args};
+    ESP_ERROR_CHECK(esp_console_cmd_register(&cat_cmd));
+}
+
+static struct {
+    struct arg_str *pattern;
+    struct arg_file *files;
+    struct arg_lit *ignore_case;
+    struct arg_lit *line_number;
+    struct arg_lit *invert_match;
+    struct arg_end *end;
+} grep_args;
+
+static int strstr_case_insensitive(const char *haystack, const char *needle)
+{
+    if (!*needle) {
+        return 1; // empty needle matches
+    }
+
+    for (const char *h = haystack; *h; h++) {
+        const char *n = needle;
+        const char *h_temp = h;
+
+        while (*h_temp && *n && (tolower((unsigned char)*h_temp) == tolower((unsigned char)*n))) {
+            h_temp++;
+            n++;
+        }
+
+        if (!*n) {
+            return 1; // found match
+        }
+    }
+    return 0; // no match
+}
+
+static int grep_line(const char *line, const char *pattern, bool ignore_case, bool invert_match)
+{
+    int match;
+    if (ignore_case) {
+        match = strstr_case_insensitive(line, pattern);
+    } else {
+        match = (strstr(line, pattern) != NULL);
+    }
+
+    if (invert_match) {
+        return !match;
+    }
+    return match;
+}
+
+static int grep_file(FILE *f, const char *pattern, bool ignore_case, bool line_number, bool invert_match, const char *filename_prefix)
+{
+    char line[256];
+    int line_num = 0;
+    int match_count = 0;
+
+    while (fgets(line, sizeof(line), f)) {
+        line_num++;
+        // Remove trailing newline
+        size_t len = strlen(line);
+        if (len > 0 && line[len - 1] == '\n') {
+            line[len - 1] = '\0';
+        }
+
+        if (grep_line(line, pattern, ignore_case, invert_match)) {
+            if (filename_prefix != NULL) {
+                printf("%s:", filename_prefix);
+            }
+            if (line_number) {
+                printf("%d:", line_num);
+            }
+            printf("%s\n", line);
+            fflush(stdout);
+            match_count++;
+        }
+    }
+    if (ferror(f)) {
+        // Don't report pipe errors (EPIPE) - that's normal ending when input is finished
+        if (errno != EPIPE) {
+            fprintf(stderr, "Error %d reading file\n", ferror(f));
+            return 1;
+        }
+    }
+
+    return (match_count > 0) ? 0 : 1;
+}
+
+static int cmd_grep(int argc, char **argv)
+{
+    int nerrors = arg_parse(argc, argv, (void **)&grep_args);
+    if (nerrors != 0) {
+        arg_print_errors(stderr, grep_args.end, argv[0]);
+        return 1;
+    }
+
+    const char *pattern = grep_args.pattern->sval[0];
+    bool ignore_case = grep_args.ignore_case->count > 0;
+    bool line_number = grep_args.line_number->count > 0;
+    bool invert_match = grep_args.invert_match->count > 0;
+
+    // If no files specified, read from stdin
+    if (grep_args.files->count == 0) {
+        return grep_file(stdin, pattern, ignore_case, line_number, invert_match, NULL);
+    }
+
+    // Process files
+    int ret = 0;
+    bool show_filename = (grep_args.files->count > 1);
+
+    for (int i = 0; i < grep_args.files->count; i++) {
+        const char *filename = grep_args.files->filename[i];
+        FILE *f = fopen(filename, "r");
+        if (f == NULL) {
+            fprintf(stderr, "grep: %s: No such file or directory\n", filename);
+            ret = 1;
+            continue;
+        }
+
+        int file_ret = grep_file(f, pattern, ignore_case, line_number, invert_match, show_filename ? filename : NULL);
+        fclose(f);
+
+        if (file_ret != 0) {
+            ret = file_ret;
+        }
+    }
+
+    return ret;
+}
+
+void register_system_shell_grep(void) {
+    grep_args.pattern = arg_str1(NULL, NULL, "PATTERN", "Search pattern");
+    grep_args.files = arg_filen(NULL, NULL, "FILE", 0, 10, "Files to search (stdin if omitted)");
+    grep_args.ignore_case = arg_lit0("i", "ignore-case", "Case-insensitive search");
+    grep_args.line_number = arg_lit0("n", "line-number", "Print line numbers");
+    grep_args.invert_match = arg_lit0("v", "invert-match", "Select non-matching lines");
+    grep_args.end = arg_end(2);
+
+    const esp_console_cmd_t cmd = {
+        .command = "grep",
+        .help = "Search for PATTERN in files or stdin",
+        .hint = NULL,
+        .func = &cmd_grep,
+        .argtable = &grep_args,
+    };
+    esp_console_cmd_register(&cmd);
+}
+
+static int cmd_echo(int argc, char **argv)
+{
+    for (int i = 1; i < argc; i++) {
+        if (i == argc - 1)
+            printf("%s\n", argv[i]);
+        else
+            printf("%s ", argv[i]);
+    }
+    return 0;
+}
+
+void register_system_shell_echo(void) {
+    const esp_console_cmd_t cmd = {
+        .command = "echo",
+        .help = "Echo arguments to stdout",
+        .hint = NULL,
+        .func = &cmd_echo,
+    };
+    esp_console_cmd_register(&cmd);
+}
+
+static int cmd_true(int argc, char **argv) {
+    return 0;
+}
+
+void register_system_shell_true(void) {
+    const esp_console_cmd_t cmd = {
+        .command = "true",
+        .help = "Do nothing, successfully",
+        .hint = NULL,
+        .func = &cmd_true,
+    };
+    esp_console_cmd_register(&cmd);
+}
+
+static int cmd_false(int argc, char **argv) {
+    return 1;
+}
+
+void register_system_shell_false(void) {
+    const esp_console_cmd_t cmd = {
+        .command = "false",
+        .help = "Do nothing, unsuccessfully",
+        .hint = NULL,
+        .func = &cmd_false,
+    };
+    esp_console_cmd_register(&cmd);
+}
+
+static struct {
+    struct arg_str *path;
+    struct arg_end *end;
+} ls_args;
+
+int cmd_ls(int argc, char **argv)
+{
+    int nerrors = arg_parse(argc, argv, (void **)&ls_args);
+    if (nerrors != 0) {
+        arg_print_errors(stderr, ls_args.end, argv[0]);
+        return 1;
+    }
+
+    const char *path = ls_args.path->sval[0];
+    if (!path)
+        return 1;
+
+    DIR *dir = opendir(path);
+    if (!dir) {
+        printf("Directory %s not found\n", path);
+        return 2;
+    }
+    while (true) {
+        struct dirent *de = readdir(dir);
+        if (!de) {
+            break;
+        }
+        char file_path[512];
+        struct stat file_stat = {};
+        snprintf(file_path, sizeof(file_path), "%s/%s", path, de->d_name);
+        stat(file_path, &file_stat);
+        printf(" %s %s %ld\n", file_path, de->d_type == DT_REG ? "<file>" : "<dir>", file_stat.st_size);
+    }
+    closedir(dir);
+
+    return 0;
+}
+
+void register_system_shell_ls(void) {
+    ls_args.path = arg_str1(NULL, NULL, "<path>", "Path to list files in");
+    ls_args.end = arg_end(2);
+    const esp_console_cmd_t ls_cmd = {.command = "ls", .help = "list files", .hint = NULL, .func = &cmd_ls, .argtable = &ls_args};
+    esp_console_cmd_register(&ls_cmd);
+}
+void register_system_shell_common(void) {
+
+    register_system_shell_tee();
+    register_system_shell_cat();
+    register_system_shell_grep();
+    register_system_shell_echo();
+    register_system_shell_true();
+    register_system_shell_false();
+    register_system_shell_ls();
+}