1. find /var -type f \( -perm o+w -o \( \( -group staff \
   	-o -group users \) -perm g+w \) \)
   

2. find ~/tmp \( -type d -name keep -prune \) \
   	-o \( -type f -atime +7 -exec rm {} \; \)
   

   tai

   find ~ -type f -atime +7 | grep -v /keep/ | xargs rm -f 
   

   Kumpikaan noista ei poista hakemistoja (tehtävä oli siinä ehkä hiukan epäselvä).

3. #! /bin/sh
   cd $1
   find . ! \( -name '*.o' -o -name a.out -o -name core \) |
   while read p ;do
     if [ -d $p ] ;then mkdir -- $2/$p
     else cp -- $p $2/$p 
     fi
   done
   

#! /bin/sh

prefix=x
while getopts :i:s: opt
  do case "$opt" in
   i) exec <"$OPTARG" ;;
   s) prefix="$OPTARG" ;;
   ?) echo "invalid option -$OPTARG" >&2
    exit 1 ;;
  esac
done
shift $((OPTIND - 1))

case "$*" in
  *[!0-9\ ]*) echo "invalid argument" >&2 
	exit 2;;
esac

count=1
while [ $# -gt 0 ] ;do
  lines=$1
  while [ "$lines" -ne 0 ] && read -r line ;do
    printf "%s\n" "$line"
    lines=$((lines-1))
  done >$prefix.$count
  count=$((count+1))
  shift
done
cat >$prefix.$count

exit 0

Tämä onnistuu sediä käyttäen paljon nopeammin (jopa 100 kertaa!):

#! /bin/sh

prefix=x
while getopts :i:s: opt
do
  case "$opt" in
   i) exec <"$OPTARG" ;;
   s) prefix="$OPTARG" ;;
   ?) echo "invalid option -$OPTARG" >&2
      exit 1 ;;
  esac
done
shift $((OPTIND - 1))

count=1
END=0
CMD=
for i in "$@" ;do
  case "$i" in
    *[!0-9]*) printf "invalid argument: '%s'\n" "$i" >&2 
	      exit 2;;
  esac
  START=$((END+1))
  END=$((START + i - 1))
  CMD="$CMD
${START},${END}w $prefix.$count"
  count=$((count+1))
done
CMD="$CMD
$((END+1)),\$w $prefix.$count"

sed -n "$CMD"

exit 0

#! /bin/sh
while getopts :i:o: opt
do case "$opt" in
  i) exec <"$OPTARG" ;;
  o) exec >"$OPTARG" ;;
esac
done
shift $((OPTIND - 1))

OLDIFS="$IFS"
IFS='|' 
line="$*"
IFS="$OLDIFS"
eval "$line"
exit 0

mutta käy se ilmankin:

#! /bin/sh
while getopts :i:o: opt
do case "$opt" in
  i) exec <"$OPTARG" ;;
  o) exec >"$OPTARG" ;;
esac
done
shift $((OPTIND - 1))
${1:-cat} | ${2:-cat} | ${3:-cat} |
${4:-cat} | ${5:-cat} | ${6:-cat} |
${7:-cat} | ${8:-cat} | ${9:-cat}

1. #! /bin/sh
   oldid=
   oldpw=
   olduid=
   oldgid=
   oldname=
   oldjunk=
   sort -t: -k1,1 -k3,3 -k5,5  $1 $2 |
   while IFS=: read id pw uid gid name junk
   do
     if [ "$id" = "$oldid" ] && [ "$uid:$name" != "$olduid:$oldname" ]
     then
       printf "%s:%s:%s:%s:%s:%s\n" "$oldid" "$oldpw" "$olduid" "$oldgid" "$oldname" "$oldjunk"
       printf "%s:%s:%s:%s:%s:%s\n" "$id" "$pw" "$uid" "$gid" "$name" "$junk"
     fi
     oldid="$id"
     oldpw="$pw"
     olduid="$uid"
     oldgid="$gid"
     oldname="$name"
     oldjunk="$junk"
   done
   

2. #! /bin/sh
   TMP1=pw1$$
   TMP2=pw2$$
   sort -t: -o $TMP1 $1 
   sort -t: -o $TMP2 $2 
   join -t: -o 1.1,1.3,1.5,2.3,2.5 $TMP1 $TMP2 |
   while IFS=: read id uid1 name1 uid2 name2 ;do
     if [ "$uid1" != "$uid2" ] || [ "$name1" != "$name2" ]
     then printf "%s,%s,%s,%s,%s\n" "$id" "$uid1" "$name1" "$uid2" "$name2" 
     fi
   done
   rm $TMP1 $TMP2
   

   tai

   #! /bin/sh
   TMP1=pw1$$
   trap "rm $TMP1" 0
   sort -t: -o $TMP1 $1 
   sort -t: $2 |
   join -t: -o 1.1,1.3,1.5,2.3,2.5 $TMP1 - |
   grep -v '.*:\(.*\):\(.*\):\1:\2$' |
   tr : ,
   

#! /bin/sh
case "$1" in
  *[!0-9]*|'') printf "'%s' is not an integer.\n" "$1" >&2
	exit 1 ;;
esac

MYDIR=./fact
DATAFILE=fact.$1
LOCKFILE=$DATAFILE.lock
mkdir -p $MYDIR 
cd $MYDIR

set -C
until >$LOCKFILE
do sleep 5
done
trap "rm -f $LOCKFILE" 0

if [ ! -f $DATAFILE ]
then
  fact=$(printf "f=1;for (i=2; i<=%s; i++) f=f*i; f\n" $1 | bc)
  count=0
else
  read junk junk fact junk count junk <$DATAFILE
fi
count=$((count+1))

printf "%s! = %s computed %d times before\n" "$1" "$fact" "$count" | tee $DATAFILE

exit 0

tai käyttäen vain shellin aritmetiikkaa (joka rajoittaa toiminnan 12:een) ja yhtä tiedostoa kaikille luvuille:

#! /bin/sh
case "$1" in
  *[!0-9]*|'') printf "'%s' is not an integer.\n" "$1" >&2
	exit 1 ;;
esac
LIMIT=12
if [ $1 -gt $LIMIT ] ;then
  printf "Sorry, I can't handle numbers bigger than %d.\n" $LIMIT >&2
  exit 2
fi

MYDIR=./fact
DATAFILE=factors
LOCKFILE=$DATAFILE.lock
TMPFILE=$DATAFILE.tmp
mkdir -p $MYDIR 
cd $MYDIR

set -C
until >$LOCKFILE
do sleep 5
done
trap "rm -f $LOCKFILE" 0

[ -f $DATAFILE ] || printf "0 1 0\n" >$DATAFILE

exec 3>&1 <$DATAFILE >$TMPFILE
while read number factorial count 
do
  last=$number
  lastfact=$factorial
  if [ $number = $1 ] ; then
    printf "%d! = %d, computed %d times before\n" $1 $factorial $count >&3
    count=$((count+1))
  fi
  printf "%d %d %d\n" $number $factorial $count
done 

number=$((last+1))
factorial=$lastfact

if [ $number -lt $1 ] ;then
  while [ $number -lt $1 ] ;do
    factorial=$((factorial * number))
    printf "%d %d %d\n" $number $factorial 0
    number=$((number+1))
  done 
  factorial=$((factorial * number))
  printf "%d %d %d\n" $number $factorial 1 
  printf "%d! = %d, computed %d times before\n" $1 $factorial $count >&3
fi 

mv $TMPFILE $DATAFILE

exit 0

#! /bin/sh
# daemon starter/stopper script
abort() {
  printf "%s: %s\n" "$0" "$1" >&2
  exit ${2:-1}
}
set -a
MYDIR=/tmp/puu
PIPE=$MYDIR/pipe
PIDFILE=$MYDIR/pid
DAEMON=./6daemon
mkdir -p $MYDIR || abort "cannot create $MYDIR" 1

case "$1" in
  start)
	[ -f $PIDFILE ] && kill -0 $(cat $PIDFILE) &&
		abort "daemon already running" 7
	rm -f $PIPE
	mkfifo $PIPE || abort "cannot create FIFO $PIPE" 2
	[ -x $DAEMON ] || abort "can't start daemon ($DAEMON)" 3
	nohup $DAEMON >&- &
	PID=$!
	printf "%d\n" $PID >$PIDFILE
	;;
  stop) [ -f $PIDFILE ] || 
		abort "can't find daemon (already dead?)" 4
	PID=$(cat $PIDFILE)
	kill $PID || abort "couldn't kill daemon (pid $PID)" 5
	;;
esac
exit 0


#! /bin/sh
# daemon script
trap "rm -f $PIPE $PIDFILE" 0
while true ;do 
    DATE=$(date)
    echo $DATE>$PIPE 
done
# exits only by signal