$ apk update
$ apk add busybox-extras
$telnet smtp.163.com 25   #telnet 確認指定端口是否開啟

$ apk add --no-cache mysql-client

$ busybox
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
copyright notices.
Usage: busybox [function [arguments]...]
   or: busybox --list[-full]
   or: busybox --install [-s] [DIR]
   or: function [arguments]...
        BusyBox is a multi-call binary that combines many common Unix
        utilities into a single executable.  Most people will create a
        link to busybox for each function they wish to use and BusyBox
        will act like whatever it was invoked as.
Currently defined functions:
        [, [[, acpid, add-shell, addgroup, adduser, adjtimex, arch, arp, arping, ash, awk, base64, basename, bbconfig, bc, beep, blkdiscard,
        blkid, blockdev, brctl, bunzip2, bzcat, bzip2, cal, cat, chattr, chgrp, chmod, chown, chpasswd, chroot, chvt, cksum, clear, cmp, comm,
        cp, cpio, crond, crontab, cryptpw, cut, date, dc, dd, deallocvt, delgroup, deluser, depmod, df, diff, dirname, dmesg, dnsdomainname,
        dos2unix, du, dumpkmap, echo, egrep, eject, env, ether-wake, expand, expr, factor, fallocate, false, fatattr, fbset, fbsplash, fdflush,
        fdisk, fgrep, find, findfs, flock, fold, free, fsck, fstrim, fsync, fuser, getopt, getty, grep, groups, gunzip, gzip, halt, hd, head,
        hexdump, hostid, hostname, hwclock, id, ifconfig, ifdown, ifenslave, ifup, init, inotifyd, insmod, install, ionice, iostat, ip, ipaddr,
        ipcalc, ipcrm, ipcs, iplink, ipneigh, iproute, iprule, iptunnel, kbd_mode, kill, killall, killall5, klogd, last, less, link, linux32,
        linux64, ln, loadfont, loadkmap, logger, login, logread, losetup, ls, lsattr, lsmod, lsof, lsusb, lzcat, lzma, lzop, lzopcat, makemime,
        md5sum, mdev, mesg, microcom, mkdir, mkdosfs, mkfifo, mkfs.vfat, mknod, mkpasswd, mkswap, mktemp, modinfo, modprobe, more, mount,
        mountpoint, mpstat, mv, nameif, nanddump, nandwrite, nbd-client, nc, netstat, nice, nl, nmeter, nohup, nologin, nproc, nsenter,
        nslookup, ntpd, od, openvt, partprobe, passwd, paste, pgrep, pidof, ping, ping6, pipe_progress, pivot_root, pkill, pmap, poweroff,
        printenv, printf, ps, pscan, pstree, pwd, pwdx, raidautorun, rdate, rdev, readahead, readlink, realpath, reboot, reformime,
        remove-shell, renice, reset, resize, rev, rfkill, rm, rmdir, rmmod, route, run-parts, sed, sendmail, seq, setconsole, setfont,
        setkeycodes, setlogcons, setpriv, setserial, setsid, sh, sha1sum, sha256sum, sha3sum, sha512sum, showkey, shred, shuf, slattach, sleep,
        sort, split, stat, strings, stty, su, sum, swapoff, swapon, switch_root, sync, sysctl, syslogd, tac, tail, tar, tee, test, time,
        timeout, top, touch, tr, traceroute, traceroute6, tree, true, truncate, tty, ttysize, tunctl, udhcpc, udhcpc6, umount, uname, unexpand,
        uniq, unix2dos, unlink, unlzma, unlzop, unshare, unxz, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, vlock, volname, watch,
        watchdog, wc, wget, which, who, whoami, whois, xargs, xxd, xzcat, yes, zcat, zcip

$ busybox-extras
BusyBox v1.36.1 (2024-06-12 06:28:12 UTC) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
copyright notices.
Usage: busybox [function [arguments]...]
   or: busybox --list[-full]
   or: busybox --install [-s] [DIR]
   or: function [arguments]...
        BusyBox is a multi-call binary that combines many common Unix
        utilities into a single executable.  Most people will create a
        link to busybox for each function they wish to use and BusyBox
        will act like whatever it was invoked as.
Currently defined functions:
        arch, conspy, dnsd, dumpleases, fakeidentd, ftpd, ftpget, ftpput, httpd, inetd, readahead, tcpsvd, telnet, telnetd, tftp, tftpd,
        udhcpd

sed -i 's/dl-cdn.alpinelinux.org/mirrors.ustc.edu.cn/g' /etc/apk/repositories

apk update

apk add curl

apk add busybox-extras