#!/bin/sh

[ -d /dev ] || mkdir -m 0755 /dev
[ -d /root ] || mkdir -m 0700 /root
[ -d /sys ] || mkdir /sys
[ -d /proc ] || mkdir /proc
[ -d /tmp ] || mkdir /tmp
mkdir -p /var/lock
mount -t sysfs -o nodev,noexec,nosuid none /sys 
mount -t proc -o nodev,noexec,nosuid none /proc

grep -q ‘\<quiet\>‘ /proc/cmdline || echo "Loading, please wait..."

# Note that this only becomes /dev on the real filesystem if udev‘s scripts
# are used; which they will be, but it‘s worth pointing out
if ! mount -t devtmpfs -o mode=0755 none /dev; then
 mount -t tmpfs -o mode=0755 none /dev
 mknod -m 0600 /dev/console c 5 1
 mknod /dev/null c 1 3
fi
mkdir /dev/pts
mount -t devpts -o noexec,nosuid,gid=5,mode=0620 none /dev/pts || true
> /dev/.initramfs-tools
mkdir /dev/.initramfs

# Export the dpkg architecture
export DPKG_ARCH=
. /conf/arch.conf

# Set modprobe env
export MODPROBE_OPTIONS="-qb"

# Export relevant variables
export ROOT=
export ROOTDELAY=
export ROOTFLAGS=
export ROOTFSTYPE=
export IPOPTS=
export HWADDR=
export break=
export init=/sbin/init
export quiet=n
export readonly=y
export rootmnt=/root
export debug=
export panic=
export blacklist=
export resume_offset=

# Bring in the main config
. /conf/initramfs.conf
for conf in conf/conf.d/*; do
 [ -f ${conf} ] && . ${conf}
done
. /scripts/functions

# Parse command line options
for x in $(cat /proc/cmdline); do
 case $x in
 init=*)
  init=${x#init=}
  ;;
 root=*)
  ROOT=${x#root=}
  case $ROOT in
  LABEL=*)
   ROOT="${ROOT#LABEL=}"

   # support / in LABEL= paths (escape to \x2f)
   case "${ROOT}" in
   *[/]*)
   if [ -x "$(command -v sed)" ]; then
    ROOT="$(echo ${ROOT} | sed ‘s,/,\\x2f,g‘)"
   else
    if [ "${ROOT}" != "${ROOT#/}" ]; then
     ROOT="\x2f${ROOT#/}"
    fi
    if [ "${ROOT}" != "${ROOT%/}" ]; then
     ROOT="${ROOT%/}\x2f"
    fi
    IFS=‘/‘
    newroot=
    for s in $ROOT; do
     if [ -z "${newroot}" ]; then
      newroot="${s}"
     else
      newroot="${newroot}\\x2f${s}"
     fi
    done
    unset IFS
    ROOT="${newroot}"
   fi
   esac
   ROOT="/dev/disk/by-label/${ROOT}"
   ;;
  UUID=*)
   ROOT="/dev/disk/by-uuid/${ROOT#UUID=}"
   ;;
  /dev/nfs)
   [ -z "${BOOT}" ] && BOOT=nfs
   ;;
  esac
  ;;
 rootflags=*)
  ROOTFLAGS="-o ${x#rootflags=}"
  ;;
 rootfstype=*)
  ROOTFSTYPE="${x#rootfstype=}"
  ;;
 rootdelay=*)
  ROOTDELAY="${x#rootdelay=}"
  case ${ROOTDELAY} in
  *[![:digit:].]*)
   ROOTDELAY=
   ;;
  esac
  ;;
 resumedelay=*)
  RESUMEDELAY="${x#resumedelay=}"
  ;;
 loop=*)
  LOOP="${x#loop=}"
  ;;
 loopflags=*)
  LOOPFLAGS="-o ${x#loopflags=}"
  ;;
 loopfstype=*)
  LOOPFSTYPE="${x#loopfstype=}"
  ;;
 cryptopts=*)
  cryptopts="${x#cryptopts=}"
  ;;
 nfsroot=*)
  NFSROOT="${x#nfsroot=}"
  ;;
 netboot=*)
  NETBOOT="${x#netboot=}"
  ;;
 ip=*)
  IPOPTS="${x#ip=}"
  ;;
 hwaddr=*)
  HWADDR="${x#hwaddr=}"
  ;;
 boot=*)
  BOOT=${x#boot=}
  ;;
 resume=*)
  RESUME="${x#resume=}"
  ;;
 resume_offset=*)
  resume_offset="${x#resume_offset=}"
  ;;
 noresume)
  noresume=y
  ;;
 panic=*)
  panic="${x#panic=}"
  case ${panic} in
  *[![:digit:].]*)
   panic=
   ;;
  esac
  ;;
 quiet)
  quiet=y
  ;;
 ro)
  readonly=y
  ;;
 rw)
  readonly=n
  ;;
 debug)
  debug=y
  quiet=n
  exec >/dev/.initramfs/initramfs.debug 2>&1
  set -x
  ;;
 debug=*)
  debug=y
  quiet=n
  set -x
  ;;
 break=*)
  break=${x#break=}
  ;;
 break)
  break=premount
  ;;
 blacklist=*)
  blacklist=${x#blacklist=}
  ;;
 netconsole=*)
  netconsole=${x#netconsole=}
  ;;
 esac
done

if [ -z "${noresume}" ]; then
 export resume=${RESUME}
else
 export noresume
fi

[ -n "${netconsole}" ] && modprobe netconsole netconsole=${netconsole}

maybe_break top

# export BOOT variable value for compcache,
# so we know if we run from casper
export BOOT

# Don‘t do log messages here to avoid confusing usplash
run_scripts /scripts/init-top

maybe_break modules
log_begin_msg "Loading essential drivers..."
load_modules
log_end_msg

maybe_break premount
[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/init-premount"
run_scripts /scripts/init-premount
[ "$quiet" != "y" ] && log_end_msg

maybe_break mount
log_begin_msg "Mounting root file system..."
. /scripts/${BOOT}
parse_numeric ${ROOT}
mountroot
log_end_msg

maybe_break bottom
[ "$quiet" != "y" ] && log_begin_msg "Running /scripts/init-bottom"
run_scripts /scripts/init-bottom
[ "$quiet" != "y" ] && log_end_msg

# Move virtual filesystems over to the real filesystem
mount -n -o move /sys ${rootmnt}/sys
mount -n -o move /proc ${rootmnt}/proc

# Check init bootarg
if [ -n "${init}" ] && [ ! -x "${rootmnt}${init}" ]; then
 echo "Target filesystem doesn‘t have ${init}."
 init=
fi

# Search for valid init
if [ -z "${init}" ] ; then
 for init in /sbin/init /etc/init /bin/init /bin/sh; do
  if [ ! -x "${rootmnt}${init}" ]; then
   continue
  fi
  break
 done
fi

# No init on rootmount
if [ ! -x "${rootmnt}${init}" ]; then
 panic "No init found. Try passing init= bootarg."
fi

# Confuses /etc/init.d/rc
if [ -n ${debug} ]; then
 unset debug
fi

# Chain to real filesystem
maybe_break init
exec run-init ${rootmnt} ${init} "$@" <${rootmnt}/dev/console >${rootmnt}/dev/console 2>&1
panic "Could not execute run-init."

没有找到linuxrc却发现Init