Lập trình nhúng trên Linux thường chạy trên các phần cứng hạn chế về tài nguyên CPU, RAM, đĩa cứng…
Vì vậy nhu cầu nấu nướng lại hệ điều hành Linux sao cho nhỏ gọn hơn, bỏ hết các thành phần không cần thiết đi giúp Linux khởi động nhanh hơn, chạy nhanh hơn, tốn ít dung lượng đĩa cứng hơn.
Alpine Linux là hệ điều hành Linux được tối ưu về dung lượng để đi theo hướng chạy trên thiết bị phần cứng nhúng (embedded system) và để chạy các phần mềm, ứng dụng đóng gói thành container.
Alpine Linux 3.19 với Busybox chỉ có các lệnh Linux sau
# cat /etc/os-release
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.19.0
PRETTY_NAME="Alpine Linux v3.19"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://gitlab.alpinelinux.org/alpine/aports/-/issues"
# busybox --help
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, zcipBusybox có thể bỏ bớt các lệnh không cần thiết cũng như bỏ bớt các tùy chọn không cần thiết trong 1 lệnh.
extract-ikconfig dùng để trích ra các giá trị đã chọn để biên dịch Linux kernel chạy trên Alpine Linux bị lỗi do lệnh grep không có tùy chọn -b.
Lỗi grep: unrecognized option: b xuất hiện nhiều lần do trong extract-ikconfig xài grep -b nhiều lần
# tool='https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/scripts/extract-ikconfig'
# curl -Os $tool
# sh extract-ikconfig /boot/vmlinuz-lts > kernel-params.txt
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
grep: unrecognized option: b
BusyBox v1.36.1 (2023-11-07 18:53:09 UTC) multi-call binary.
Usage: grep [-HhnlLoqvsrRiwFE] [-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
-R Recurse and dereference symlinks
-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
extract-ikconfig: Cannot find kernel config.Busybox được xài trên Alpine Linux làm tiến trình init 1 thay thế systemd nặng cồng kềnh.
# cat /etc/os-release
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.19.0
PRETTY_NAME="Alpine Linux v3.19"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://gitlab.alpinelinux.org/alpine/aports/-/issues"
# ls -l /sbin/init
lrwxrwxrwx 1 root root 12 Jan 23 00:41 /sbin/init -> /bin/busybox
# pstree -p
init(1)─┬─acpid(3396)
├─chronyd(3425)
├─crond(3452)
├─getty(3496)
├─getty(3500)
├─getty(3504)
├─getty(3507)
├─getty(3512)
├─login(3495)───ash(3516)
├─sshd(3488)───sshd(3518)───ash(3520)───pstree(3626)
├─syslogd(3369)
└─udhcpc(3304)
# apk info busybox
busybox-1.36.1-r15 description:
Size optimized toolbox of many common UNIX utilities
busybox-1.36.1-r15 webpage:
https://busybox.net/
busybox-1.36.1-r15 installed size:
924 KiB