## Busybox ### 簡介  BusyBox 是一個集成了一百多個最常用 Linux 命令和工具（如 cat、echo、grep、mount、telnet 等）的精簡工具箱，它只需要幾 MB 的大小，很方便進行各種快速驗證，被譽為“Linux 系統的瑞士軍刀”。 BusyBox 可運行于多款 POSIX 環境的操作系統中，如 Linux（包括 Android）、Hurd、FreeBSD 等。 ### 獲取官方鏡像 在 Docker Hub 中搜索 busybox 相關的鏡像。 ```bash $ docker search busybox NAME DESCRIPTION STARS OFFICIAL AUTOMATED busybox 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] ... ``` 讀者可以看到最受歡迎的鏡像同時帶有 OFFICIAL 標記，說明它是官方鏡像。用戶使用 docker pull 指令下載鏡像 `busybox:latest`： ```bash $ docker pull busybox:latest busybox:latest: The image you are pulling has been verified e433a6c5b276: Pull complete e72ac664f4f0: Pull complete 511136ea3c5a: Pull complete df7546f9f060: Pull complete Status: Downloaded newer image for busybox:latest ``` 下載后，可以看到 busybox 鏡像只有2.433 MB： ```bash $ docker image ls REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE busybox latest e72ac664f4f0 6 weeks ago 2.433 MB ``` ### 運行 busybox 啟動一個 busybox 容器，并在容器中執行 grep 命令。 ```bash $ docker run -it busybox / # grep BusyBox 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 ``` 查看容器內的掛載信息。 ```bash / # mount rootfs 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 鏡像雖然小巧，但包括了大量常見的 Linux 命令，讀者可以用它快速熟悉 Linux 命令。 ### 相關資源 * `Busybox` 官網：https://busybox.net/ * `Busybox` 官方倉庫：https://git.busybox.net/busybox/ * `Busybox` 官方鏡像：https://hub.docker.com/_/busybox/ * `Busybox` 官方倉庫：https://github.com/docker-library/busybox