# 构建日志统一收集
make > build.log 2>&1

# 一边看一边保存
./run_tests.sh | tee test.log

# 统计错误行数
grep "ERROR" app.log | wc -l

find <path...> <条件...> <动作>

# 找出所有 C 源文件
find src -type f -name "*.c"

# 排除 build 目录
find . -path ./build -prune -o -name "*.log" -print

# 递归查 TODO
grep -rn "TODO" src

# 找多个关键词
grep -E "error|fatal|panic" app.log

# 反向筛选非空行
grep -v "^$" README.md

sed [选项] '<地址><命令>' file

# 1) 预览替换（不改文件）
sed 's/^DEBUG=.*/DEBUG=false/' .env

# 2) 原地替换（建议先备份）
sed -i.bak 's/^DEBUG=.*/DEBUG=false/' .env

# 3) 提取某段日志（起止模式）
sed -n '/BEGIN/,/END/p' app.log

# 4) 只看去掉注释和空行后的配置
sed '/^#/d;/^$/d' conf.ini

awk [选项] 'pattern { action }' file

# 1) 输出文件前 10 行的第 1、2 列
awk 'NR<=10 {print $1, $2}' access.log

# 2) CSV 处理（逗号分隔）
awk -F, 'NR==1 {print "name,score"; next} {print $1 "," $3}' score.csv

# 3) 统计状态码分布（假设第 9 列是状态码）
awk '{code[$9]++} END {for (c in code) print c, code[c]}' access.log

# 4) 多文件处理时区分文件名
awk '{print FILENAME, FNR, $0}' a.txt b.txt

# 安全批量 grep
find src -name "*.c" -print0 | xargs -0 grep -n "TODO"

# 每次处理 10 个参数
find . -name "*.jpg" | xargs -n 10 echo

# 一步编译链接
gcc main.c -o app

# 分步编译
gcc -c main.c -o main.o
gcc -c util.c -o util.o
gcc main.o util.o -o app

gcc -std=c11 -Wall -Wextra -g src/main.c -o app

CC := gcc
CFLAGS := -std=c11 -Wall -Wextra -g -O2
TARGET := app
SRCDIR := src
OBJDIR := build
SOURCES := $(wildcard $(SRCDIR)/*.c)
OBJECTS := $(patsubst $(SRCDIR)/%.c,$(OBJDIR)/%.o,$(SOURCES))

.PHONY: all clean run

all: $(TARGET)

$(TARGET): $(OBJECTS)
	$(CC) $(CFLAGS) $^ -o $@

$(OBJDIR)/%.o: $(SRCDIR)/%.c | $(OBJDIR)
	$(CC) $(CFLAGS) -c $< -o $@

$(OBJDIR):
	mkdir -p $(OBJDIR)

run: $(TARGET)
	./$(TARGET)

clean:
	rm -rf $(OBJDIR) $(TARGET)

make        # 构建
make run    # 运行
make clean  # 清理

#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
cd "$ROOT_DIR"

LOG_DIR="logs"
mkdir -p "$LOG_DIR"

echo "[1/4] lint-like scan"
find src -name "*.c" -print0 | xargs -0 grep -nE "TODO|FIXME" || true

echo "[2/4] build"
make >"$LOG_DIR/build.log" 2>&1

echo "[3/4] run"
./app >"$LOG_DIR/run.log" 2>&1

echo "[4/4] done"
echo "build log: $LOG_DIR/build.log"
echo "run log:   $LOG_DIR/run.log"

# 判断“第一个参数是否为空或未传”
if [[ -z "${1:-}" ]]; then
  echo "first argument is empty"
fi

# 判断“是否根本没传任何参数”
if [[ $# -eq 0 ]]; then
  echo "no arguments provided"
fi

# 区分“没传”和“传了空字符串”
if [[ $# -eq 0 ]]; then
  echo "missing argument"
elif [[ -z "$1" ]]; then
  echo "argument is an empty string"
else
  echo "argument = $1"
fi

#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
cd "$ROOT_DIR"

LOG_DIR="logs"
mkdir -p "$LOG_DIR"

log() {
  printf '[%s] %s\n' "$(date '+%H:%M:%S')" "$*"
}

require_cmd() {
  local cmd="$1"
  if ! command -v "$cmd" >/dev/null 2>&1; then
    echo "missing command: $cmd" >&2
    exit 1
  fi
}

scan_todo() {
  log "scan TODO/FIXME in src"
  find src -name "*.c" -print0 | xargs -0 grep -nE "TODO|FIXME" || true
}

build_target() {
  local mode="${1:-debug}"
  case "$mode" in
    debug) CFLAGS_EXTRA="-O0 -g" ;;
    release) CFLAGS_EXTRA="-O2 -DNDEBUG" ;;
    *)
      echo "usage: $0 [debug|release]" >&2
      exit 2
      ;;
  esac
  log "build mode=$mode"
  make CFLAGS_EXTRA="$CFLAGS_EXTRA" >"$LOG_DIR/build-$mode.log" 2>&1
}

run_with_checks() {
  if [[ ! -x ./app ]]; then
    echo "binary ./app not found or not executable" >&2
    return 1
  fi
  log "run app"
  ./app >"$LOG_DIR/run.log" 2>&1
}

main() {
  local mode="${1:-debug}"
  local required=(find xargs grep make)
  local cmd
  for cmd in "${required[@]}"; do
    require_cmd "$cmd"
  done

  scan_todo
  build_target "$mode"

  local i=0
  while [[ $i -lt 1 ]]; do
    run_with_checks || true
    i=$((i + 1))
  done

  log "done"
  log "build log: $LOG_DIR/build-$mode.log"
  log "run log:   $LOG_DIR/run.log"
}

main "$@"

chmod +x build.sh
./build.sh           # debug
./build.sh release   # release

# 1) 定位源码文件
find src -type f \( -name "*.c" -o -name "*.h" \)

# 2) 搜索待处理标记
find src -name "*.c" -print0 | xargs -0 grep -nE "TODO|FIXME"

# 3) 预览替换
find src -name "*.c" -print0 | xargs -0 sed 's/old_api/new_api/g'

# 4) 构建并保存日志
make > build.log 2>&1