Question

Busybox

简介

图 1.21.1.1 - Busybox - Linux 瑞士军刀

BusyBox 是一个集成了一百多个最常用 Linux 命令和工具（如 cat、echo、grep、mount、telnet 等）的精简工具箱，它只需要几 MB 的大小，很方便进行各种快速验证，被誉为“Linux 系统的瑞士军刀”。

BusyBox 可运行于多款 POSIX 环境的操作系统中，如 Linux（包括 Android）、Hurd、FreeBSD 等。

获取官方镜像

在 Docker Hub 中搜索 busybox 相关的镜像。

$ docker search busyboxNAME                            DESCRIPTION                                     STARS     OFFICIAL   AUTOMATEDbusybox                         Busybox base image.                             755       [OK]progrium/busybox                                                                63                   [OK]radial/busyboxplus              Full-chain, Internet enabled, busybox made...   11                   [OK]odise/busybox-python                                                            3                    [OK]multiarch/busybox               multiarch ports of ubuntu-debootstrap           2                    [OK]azukiapp/busybox                This image is meant to be used as the base...   2                    [OK]...

读者可以看到最受欢迎的镜像同时带有 OFFICIAL 标记，说明它是官方镜像。用户使用 docker pull 指令下载 busybox:latest 镜像：

$ docker pull busybox:latestbusybox:latest: The image you are pulling has been verifiede433a6c5b276: Pull completee72ac664f4f0: Pull complete511136ea3c5a: Pull completedf7546f9f060: Pull completeStatus: Downloaded newer image for busybox:latest

下载后，可以看到 busybox 镜像只有 2.433 MB：

$ docker image lsREPOSITORY                   TAG                 IMAGE ID            CREATED             VIRTUAL SIZEbusybox                   latest              e72ac664f4f0        6 weeks ago         2.433 MB

运行 busybox

启动一个 busybox 容器，并在容器中执行 grep 命令。

$ docker run -it busybox/ # grepBusyBox v1.22.1 (2014-05-22 23:22:11 UTC) multi-call binary.Usage: grep [-HhnlLoqvsriwFE] [-m N] [-A/B/C N] PATTERN/-e PATTERN.../-f FILE [FILE]...Search for PATTERN in FILEs (or stdin)        -H      Add 'filename:' prefix        -h      Do not add 'filename:' prefix        -n      Add 'line_no:' prefix        -l      Show only names of files that match        -L      Show only names of files that don't match        -c      Show only count of matching lines        -o      Show only the matching part of line        -q      Quiet. Return 0 if PATTERN is found, 1 otherwise        -v      Select non-matching lines        -s      Suppress open and read errors        -r      Recurse        -i      Ignore case        -w      Match whole words only        -x      Match whole lines only        -F      PATTERN is a literal (not regexp)        -E      PATTERN is an extended regexp        -m N    Match up to N times per file        -A N    Print N lines of trailing context        -B N    Print N lines of leading context        -C N    Same as '-A N -B N'        -e PTRN Pattern to match        -f FILE Read pattern from file

查看容器内的挂载信息。

/ # mountrootfs on / type rootfs (rw)none on / type aufs (rw,relatime,si=b455817946f8505c)proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)tmpfs on /dev type tmpfs (rw,nosuid,mode=755)shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=65536k)devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)sysfs on /sys type sysfs (ro,nosuid,nodev,noexec,relatime)/dev/disk/by-uuid/b1f2dba7-d91b-4165-a377-bf1a8bed3f61 on /etc/resolv.conf type ext4 (rw,relatime,errors=remount-ro,data=ordered)/dev/disk/by-uuid/b1f2dba7-d91b-4165-a377-bf1a8bed3f61 on /etc/hostname type ext4 (rw,relatime,errors=remount-ro,data=ordered)/dev/disk/by-uuid/b1f2dba7-d91b-4165-a377-bf1a8bed3f61 on /etc/hosts type ext4 (rw,relatime,errors=remount-ro,data=ordered)devpts on /dev/console type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)proc on /proc/sys type proc (ro,nosuid,nodev,noexec,relatime)proc on /proc/sysrq-trigger type proc (ro,nosuid,nodev,noexec,relatime)proc on /proc/irq type proc (ro,nosuid,nodev,noexec,relatime)proc on /proc/bus type proc (ro,nosuid,nodev,noexec,relatime)tmpfs on /proc/kcore type tmpfs (rw,nosuid,mode=755)

busybox 镜像虽然小巧，但包括了大量常见的 Linux 命令，读者可以用它快速熟悉 Linux 命令。

相关资源

• Busybox 官网：https://busybox.net/
• Busybox 官方仓库：https://git.busybox.net/busybox/
• Busybox 官方镜像：https://hub.docker.com/_/busybox/
• Busybox 官方仓库：https://github.com/docker-library/busybox