linux for f in?linux link命令
大家好,感谢邀请,今天来为大家分享一下linux for f in的问题,以及和linux link命令的一些困惑,大家要是还不太明白的话,也没有关系,因为接下来将为大家分享,希望可以帮助到大家,解决大家的问题,下面就开始吧!
嵌入式linux和嵌入式android系统有什么区别和联系
嵌入式android源码架构:uboot+linux kernel+android(包含文件系统,虚拟机,UI)
嵌入式linux:这是大部分人认识的linux uboot+linux kernel+文件系统+QT(UI),
当然两者的linux内核因为上层UI的不同会稍有差别,不过还是非常接近的,做过linux的人可以无缝切换到android底层开发,所以大家说的学习android系统,其实最重要的就是学习linux驱动,再加一下android下的专门的HAL,JNI,java等等,不过大公司android相关部分也是专门的人做的了。
甚至连QT都不用了,因为linux很多设备都是没有UI的,所以要来干啥?直接无界面,照样是嵌入式linux。
现在大家说的什么嵌入式debian,ubuntu,其实也是站在linux巨人的肩膀上,其实都不算是linux的分支,只算是linux的延伸,小变化而已。看到这里大家知道嵌入式linux的强大了吧,反正是比wince强大N倍啊。
O(∩_∩)O~,所以啊,学习嵌入式android,其实底下就是学习uboot,linux内核啊,不会搞这些就像搞应用一样,所以大家以为android就是java,是非常片面的。
以前老的,说了一下区别,可以参考一下
ARCH--这是Android修改了arch/arm下面的一些文件:
arch/arm:
Chg: arch/arm/kernel/entry-armv.S
Chg: arch/arm/kernel/module.c
Chg: arch/arm/kernel/process.c
Chg: arch/arm/kernel/ptrace.c
Chg: arch/arm/kernel/setup.c
Chg: arch/arm/kernel/signal.c
Chg: arch/arm/kernel/traps.c
Chg: arch/arm/mm/cache-v6.S
Chg: arch/arm/vfp/entry.S
Chg: arch/arm/vfp/vfp.h
Chg: arch/arm/vfp/vfphw.S
Chg: arch/arm/vfp/vfpmodule.c
Goldfish--这是Android为了模拟器所开发的一个虚拟硬件平台。Goldfish执行arm926T指令(在2.6.29中,goldfish也支持ATMv7指令),但是在实际的设备中,该虚拟平台的文件不会被编译。
arch/arm/mach-goldfish:
New: arch/arm/mach-goldfish/audio.c
New: arch/arm/mach-goldfish/board-goldfish.c
New: arch/arm/mach-goldfish/pdev_bus.c
New: arch/arm/mach-goldfish/pm.c
New: arch/arm/mach-goldfish/switch.c
New: arch/arm/mach-goldfish/timer.c
YAFFS2--和PC把文件存储在硬盘上不一样,移动设备一般把Flash作为存储设备。尤其是NAND flash应用非常广泛(绝大多数手机用的都是NAND flash,三星的一些手机使用的是OneNAND)。NAND flash具有低成本和高密度的优点。
YAFFS2是“Yet Another Flash File System, 2nd edition"的简称。它提供在Linux内核和NAND flash设备之前高效率的接口。 YAFFS2并没有包含在标准的Linux内核中, Google把它添加到了Android的kernel
fs/yaffs2:
New: fs/yaffs2/devextras.h
New: fs/yaffs2/Kconfig
New: fs/yaffs2/Makefile
New: fs/yaffs2/moduleconfig.h
New: fs/yaffs2/yaffs_checkptrw.c
New: fs/yaffs2/yaffs_checkptrw.h
New: fs/yaffs2/yaffs_ecc.c
New: fs/yaffs2/yaffs_ecc.h
New: fs/yaffs2/yaffs_fs.c
New: fs/yaffs2/yaffs_getblockinfo.h
New: fs/yaffs2/yaffs_guts.c
New: fs/yaffs2/yaffs_guts.h
New: fs/yaffs2/yaffsinterface.h
New: fs/yaffs2/yaffs_mtdif1.c
New: fs/yaffs2/yaffs_mtdif1.h
New: fs/yaffs2/yaffs_mtdif2.c
New: fs/yaffs2/yaffs_mtdif2.h
New: fs/yaffs2/yaffs_mtdif.c
New: fs/yaffs2/yaffs_mtdif.h
New: fs/yaffs2/yaffs_nand.c
New: fs/yaffs2/yaffs_nandemul2k.h
New: fs/yaffs2/yaffs_nand.h
New: fs/yaffs2/yaffs_packedtags1.c
New: fs/yaffs2/yaffs_packedtags1.h
New: fs/yaffs2/yaffs_packedtags2.c
New: fs/yaffs2/yaffs_packedtags2.h
New: fs/yaffs2/yaffs_qsort.c
New: fs/yaffs2/yaffs_qsort.h
New: fs/yaffs2/yaffs_tagscompat.c
New: fs/yaffs2/yaffs_tagscompat.h
New: fs/yaffs2/yaffs_tagsvalidity.c
New: fs/yaffs2/yaffs_tagsvalidity.h
New: fs/yaffs2/yportenv.h
Bluetooth-- Google为Bluetooth打上了patch,fix了一些Bluetooth的bug
drivers/bluetooth:
Chg: drivers/bluetooth/bfusb.c
Chg: drivers/bluetooth/bt3c_cs.c
Chg: drivers/bluetooth/btusb.c
Chg: drivers/bluetooth/hci_h4.c
Chg: drivers/bluetooth/hci_ll.c
Scheduler--对于Scheduler的改变非常小,我对它并没有去研究。
Chg: kernel/sched.c
New Android Functionality--除了fix一些bug以及其他一些小的更改,Android增加了一些新的功能,介绍如下:
IPC Binder-- The IPC Binder is an Inter-Process Communication(IPC) mechanism. It allows processes to provide services to other processes via a set of higher-level APIs than are available in standard Linux. An Internet search indicated that the Binder concept originated at Be, Inc., and then made its way into Palm's software, before Google wrote a new Binder for Android.
New: drivers/staging/android/binder.c
Low Memory Killer-- Android adds a low-memory killer that, each time it's called, scans the list of running Linux processes, and kills one. It was not clear in our cursory examination why Android adds a low-memory killer on top of the already existing one in the standard Linux kernel.
New: drivers/staging/android/lowmemorykiller.c
Ashmem-- Ashmem is an Anonymous SHared MEMory system that adds interfaces so processes can share named blocks of memory. As an example, the system could use Ashmem to store icons, which multiple processes could then access when drawing their UI. The advantage of Ashmem over traditional Linux shared memory is that it provides a means for the kernel to reclaim these shared memory blocks if they are not currently in use. If a process then tries to access a shared memory block the kernel has freed, it will receive an error, and will then need to reallocate the block and reload the data.
New: mm/ashmem.c
RAM Console and Log Device-- To aid in debugging, Android adds the ability to store kernel log messages to a RAM buffer. Additionally, Android adds a separate logging module so that user processes can read and write user log messages.
New: drivers/staging/android/ram_console.c
Android Debug Bridge-- Debugging embedded devices can best be described as challenging. To make debugging easier, Google created the Android Debug Bridge(ADB), which is a protocol that runs over a USB link between a hardware device running Android and a developer writing applications on a desktop PC.
drivers/usb/gadget:
New: drivers/usb/gadget/android.c
Chg: drivers/usb/gadget/composite.c
Chg: drivers/usb/gadget/f_acm.c
New: drivers/usb/gadget/f_acm.h
New: drivers/usb/gadget/f_adb.c
New: drivers/usb/gadget/f_adb.h
New: drivers/usb/gadget/f_mass_storage.c
New: drivers/usb/gadget/f_mass_storage.h
Android also adds a new real-time clock, switch support, and timed GPIO support. We list the impacted files for these new modules at the end of this document.
Power Management-- Power management is one of the most difficult pieces to get right in mobile devices, so we split it out into a group separate from the other pieces. It's interesting to note that Google added a new power management system to Linux, rather than reuse what already existed. We list the impacted files at the end of this document.
kernel/power:
New: kernel/power/consoleearlysuspend.c
New: kernel/power/earlysuspend.c
New: kernel/power/fbearlysuspend.c
Chg: kernel/power/main.c
Chg: kernel/power/power.h
Chg: kernel/power/process.c
New: kernel/power/userwakelock.c
New: kernel/power/wakelock.c
Miscellaneous Changes-- In addition to the above, we found a number of changes that could best be described as,'Miscellaneous.' Among other things, these changes include additional debugging support, keypad light controls, and management of TCP networking
... id-to-a-new-device/
linux怎么删除当前目录下的所有文件
1.首先,安装SHH远程软件,连接到linux服务器,然后使用SSH登录到linux服务器;
2.其次,新建文件夹,其中将显示日期和时间以及一些特定参数;
3.接着,在linux下,rm是删除命令,先查看rm的帮助说明,然后使用rm test删除文件;
4.提示无法删除目录,即rm没有参数时,只能删除文件,不能删除文件夹;
5.最后,进行删除操作时不要使用-rf参数,请使用rm-rf test直接删除目录下的所有文件而不删除文件夹。
自己动手在Linux系统实现一个everything程序
大家好,我是良许。
在 Linux系统中,我们可以实现一个轻巧的"everything"程序。它能快速搜索文件或目录,提供类似于 Windows下的 Everything工具的体验。Linux有多个强大的替代品,如 locate, Catfish和 Tracker,但自己动手实现一个程序能帮助我们提升技术,满足个性化需求,并在程序员圈内展示自己的技术。
实现方法如下:
1.创建一个名为"lazy_find.sh"的脚本文件,并将以下简洁的脚本内容复制进去。
bash
#!/bin/bash
for f in$(find"$@"-type f); do
echo$f
done
保存并退出。
2.赋予脚本可执行权限:
bash
chmod+x lazy_find.sh
3.使用脚本搜索文件。基本用法是在脚本名称后面跟上要搜索的文件名称,支持模糊搜索:
bash
lazy_find.sh scr
结果会显示匹配的文件和目录。如需区分大小写,添加 `-m`选项:
bash
lazy_find.sh-m Scr
结果仅显示匹配的文件。
若想搜索指定目录,使用 `--path`参数:
bash
lazy_find.sh--path/home/search/hello
结果将显示包含"hello"的文件或目录。
4.自定义命令调用脚本,实现一键搜索功能。在.bashrc文件中添加以下语句:
bash
alias lf='lazy_find.sh'
重启终端或运行 `source~/.bashrc`使修改生效。
总结,通过学习这段脚本,我们可以提升 Shell编程能力,并掌握自定义命令调用脚本的方法。本文适合 Linux初学者入门。