Linux
busybox tar 或將大文件拆分為多個小文件
我在 at91sam9g20 上執行 Linux 版本 3.4.8。
我想獲取一個大記錄並將其拆分為多個文件。我嘗試了多種方法，但似乎都沒有正常工作，例如
tar -c -M --tape-length=102400 --file=disk1.tar mytest.tar.g z tar: invalid option -- M BusyBox v1.20.2 (2012-09-24 16:21:25 CEST) multi-call binary. Usage: tar -[cxthvO] [-X FILE] [-T FILE] [-f TARFILE] [-C DIR] [FILE]... Create, extract, or list files from a tar file Operation: c Create x Extract t List f Name of TARFILE ('-' for stdin/out) C Change to DIR before operation v Verbose O Extract to stdout h Follow symlinks exclude File to exclude X File with names to exclude T File with names to include似乎busybox有一個精簡版的tar，它不允許某些參數。
當我嘗試拆分時，我得到以下資訊：
/:# split -sh: split: 未找到
有沒有使用busybox命令集將大文件拆分為多個文件的方法？
Currently defined functions: [, [[, addgroup, adduser, ar, arping, ash, awk, basename, blkid, bunzip2, bzcat, cat, catv, chattr, chgrp, chmod, chown, chroot, chrt, chvt, cksum, clear, cmp, cp, cpio, crond, crontab, cut, date, dc, dd, deallocvt, delgroup, deluser, devmem, df, diff, dirname, dmesg, dnsd, dnsdomainname, dos2unix, du, dumpkmap, echo, egrep, eject, env, ether-wake, expr, false, fdflush, fdformat, fgrep, find, fold, free, freeramdisk, fsck, fuser, getopt, getty, grep, gunzip, gzip, halt, hdparm, head, hexdump, hostid, hostname, hwclock, id, ifconfig, ifdown, ifup, inetd, init, insmod, install, ip, ipaddr, ipcrm, ipcs, iplink, iproute, iprule, iptunnel, kill, killall, killall5, klogd, last, less, linux32, linux64, linuxrc, ln, loadfont, loadkmap, logger, login, logname, losetup, ls, lsattr, lsmod, lsof, lspci, lsusb, lzcat, lzma, makedevs, md5sum, mdev, mesg, microcom, mkdir, mkfifo, mknod, mkswap, mktemp, modprobe, more, mount, mountpoint, mt, mv, nameif, netstat, nice, nohup, nslookup, od, openvt, passwd, patch, pidof, ping, pipe_progress, pivot_root, poweroff, printenv, printf, ps, pwd, rdate, readlink, readprofile, realpath, reboot, renice, reset, resize, rm, rmdir, rmmod, route, run-parts, runlevel, sed, seq, setarch, setconsole, setkeycodes, setlogcons, setserial, setsid, sh, sha1sum, sha256sum, sha512sum, sleep, sort, start-stop-daemon, strings, stty, su, sulogin, swapoff, swapon, switch_root, sync, sysctl, syslogd, tail, tar, tee, telnet, test, tftp, time, top, touch, tr, traceroute, true, tty, udhcpc, umount, uname, uniq, unix2dos, unlzma, unxz, unzip, uptime, usleep, uudecode, uuencode, vconfig, vi, vlock, watch, watchdog, wc, wget, which, who, whoami, xargs, xz, xzcat, yes, zcat
您可以使用
dd帶有bs,count和skip參數的 busybox 小程序將大文件拆分成塊。
dd手冊頁部分來自busybox：dd
$$ if=FILE $$ $$ of=FILE $$ $$ ibs=N $$ $$ obs=N $$ $$ bs=N $$ $$ count=N $$ $$ skip=N $$
$$ seek=N $$ $$ conv=notrunc|noerror|sync|fsync $$
Copy a file with converting and formatting if=FILE Read from FILE instead of stdin of=FILE Write to FILE instead of stdout bs=N Read and write N bytes at a time ibs=N Read N bytes at a time obs=N Write N bytes at a time count=N Copy only N input blocks skip=N Skip N input blocks seek=N Skip N output blocks conv=notrunc Don't truncate output file conv=noerror Continue after read errors conv=sync Pad blocks with zeros conv=fsync Physically write data out before finishing所以基本上你會做這樣的事情：
$ dd if=bigfile of=part.0 bs=1024 count=1024 skip=0 $ dd if=bigfile of=part.1 bs=1024 count=1024 skip=1024 $ dd if=bigfile of=part.2 bs=1024 count=1024 skip=2048對於每個
part.X文件dd寫入count * bs bytes忽略skip輸入文件中的第一個字節。一個非常基本的單行（結合
sed，xargs和dd來自busybox的小程序）可能看起來像這樣：seq 0 19 | xargs -n1 sh -c 'dd if=bigfile of=part.$0 bs=1024 count=1024 skip=$(expr $0 \* 1024)'
part.X最多生成 20 個1048576 bytes大小的文件。範例拆分
bigfile：$ ls -l total 2940 -rw-rw-r-- 1 user user 3000000 Apr 27 13:21 bigfile $ seq 0 20 | xargs -n1 sh -c 'dd if=bigfile of=part.$0 bs=1024 count=1024 skip=$(expr $0 \* 1024)' 1024+0 records in 1024+0 records out 1024+0 records in 1024+0 records out 881+1 records in 881+1 records out 0+0 records in 0+0 records out [...] $ ls -l total 5968 -rw-rw-r-- 1 user user 3000000 Apr 27 13:21 bigfile -rw-rw-r-- 1 user user 1048576 Apr 27 13:43 part.0 -rw-rw-r-- 1 user user 1048576 Apr 27 13:43 part.1 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.10 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.11 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.12 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.13 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.14 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.15 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.16 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.17 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.18 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.19 -rw-rw-r-- 1 user user 902848 Apr 27 13:43 part.2 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.3 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.4 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.5 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.6 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.7 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.8 -rw-rw-r-- 1 user user 0 Apr 27 13:43 part.9
cat可以使用（或dd再次使用seek參數）輕鬆完成恢復。0字節文件可以跳過：$ cat part.0 part.1 part.2 > bigfile.res $ diff bigfile bigfile.res根據您的需要，您不應該使用
seq和計算大文件的特定大小，而是在 shell 腳本中執行所有操作。