fs/skeleton/bin/kernopt

#!/bin/sh
# Usage:
#   kernopt [names...]
#
# Prints exactly one line containing the value for each "name." We read
# /proc/cmdline and parse all the key=value pairs, printing the 'value' part
# if an entry exists where key=name.  If the "=value" part is missing, the
# value is 1.  If there is no matching key, the value is the empty string.
#
# We also look in the environment variable KERNEL_EXTRA for additional
# options that take precedence over /proc/cmdline.  This is mostly to allow
# easier testing of scripts that call this one without rebooting over and
# over.
#

for want in "$@"; do
  # This would be easier with sed, but our rootfs currently doesn't have sed.
  # So we do this slightly insane loop to split on both lines and words.
  {
    echo "$KERNEL_EXTRA"
    while read line; do
      echo "$line"
    done </proc/cmdline
  } | {
    while read line; do
      set -- $line
      for i in "$@"; do
        echo "$i"
      done
    done
  } | {
    while IFS== read key value; do
      [ "$key" = "$want" ] && echo "${value:=1}" && exit 0
    done
    echo  # default value
  }
done