解决Linux Bash Shell脚本中脚本对文件内容修改未保存的问题

# 示例1：直接原地修改的陷阱
sed -i 's/old/new/g' target.txt
echo "追加内容" >> target.txt

# 示例2：使用临时文件的原子操作
tmpfile=$(mktemp)
process_data < input.txt > $tmpfile
mv $tmpfile input.txt

# 示例3：全量重定向标准模式
{
    sed 's/old/new/g'
    echo "追加内容"
} < source.txt > source.txt.tmp
mv source.txt.tmp source.txt

# 示例4：使用moreutils工具包
sudo apt install moreutils  # Debian系安装命令

sed 's/old/new/g' file.txt | sponge file.txt

# 示例5：利用/dev/shm实现内存暂存
tmp_path="/dev/shm/$(basename $0).tmp"
grep "error" /var/log/syslog > $tmp_path
mv $tmp_path /var/log/syslog

# 示例6：使用flock进行进程锁
(
    flock -x 200
    sed -i 's/old/new/g' target.txt
    echo "追加内容" >> target.txt
) 200>target.txt.lock

# 示例7：结合git实现版本追踪
git checkout -b script-modification
sed -i 's/old/new/g' important.conf
git commit -am "Auto modification"
git checkout main

# 示例8：分块处理大文件
while IFS= read -r line; do
    modified_line=$(process "$line")
    echo "$modified_line" >> output.tmp
done < input.txt
mv output.tmp input.txt

# 示例9：使用Python辅助处理
python3 -c '
import sys, os
with open("data.txt", "r+") as f:
    content = f.read().replace("old", "new")
    f.seek(0)
    f.write(content)
    f.truncate()
'

# 示例10：时间戳备份方案
backup_file="data_$(date +%Y%m%d%H%M%S).bak"
cp -p data.txt $backup_file

# 示例11：权限检查与提示
if [[ ! -w /etc/nginx.conf ]]; then
    echo "请使用sudo执行" >&2
    exit 1
fi

# 示例12：带错误处理的替换脚本
set -eo pipefail
tmpfile=$(mktemp)
trap 'rm -f $tmpfile' EXIT

sed 's/old/new/g' input.txt > $tmpfile || exit 1
mv $tmpfile input.txt