Example Commands
# Execute multiple commands on one line
$ pwd ; ls tmp ; print "Hello world"
# Run the find command in the background
$ find . —name tmp.out —print &
# Connect the output of who to grep
$ who | grep fred
# Talk to fred if he is logged on
$ {who | grep fred ;} && talk fred
# Send ls output to ls.out, even if noclobber is set
$ ls >| ls.out
# Append output of ls to ls.out
$ ls >> ls.out
# Send invite.txt to dick, jane, and spot
$ mail dick jane spot < invite.txt
# List file names that begin with z
$ ls z*
# List two, three, and four character file names
$ ls ?? ??? ????
# List file names that begin with a, b, or c
$ ls [a-c]*
# List file names that do not end with.c
$ ls *[!.c]
# List file names that contain any number of consecutive x's
$ ls *(x)
# List file names that contain only numbers
$ ls +([0-9])
# List file names that do not end in.c,.Z, or .o
$ ls !(*.c|*.Z|*.o)
# Set NU to the number of users that are logged on
$ NU=$(who | wc —l)
# Set HOSTS to the contents of the /etc/hosts file
$ HOSTS=$(</etc/hosts)
# Set TOTAL to the sum of 4 + 3
$ TOTAL=$((4+3))
# Change directory to jane's home directory
$ cd ∼jane
# Set the right-justify attribute on variable SUM and set it to 70
$ typeset —R SUM=70
# Set and export the variable LBIN
$ typeset —x LBIN=/usr/lbin
# Set the field width of SUM to 5
$ typeset —R5 SUM
# Remove the lowercase attribute from MSYS
$ typeset +l MSYS
# Unset variable LBIN
$ unset LBIN
# Display the length of variable FNAME
$ print ${#FNAME}
# Set SYS to the hostname if not set, then display its value
$ print ${SYS:=$(hostname)}
# Display an error message if XBIN is not set
$ : ${XBIN:?}
# Display the base directory in LBIN
$ print ${LBIN##*/}
# Set array variable MONTHS to the first four month names
$ set —A MONTHS jan feb mar apr
# Display element 3 of the XBUF array variable
$ print ${XBUF[3]}
# Display the length of the TMP array element 2
$ print ${#TMP[2]}
# Display $HOME set to /home/anatole
$ print '$HOME set to' $HOME
# Display the value of $ENV
$ print $ENV
# Display the last five commands from the history file
$ history —5
# Retrieve last print command in vi edit mode
$ set —o vi; <ESCAPE>/^print<RETURN>
# Bring background job 3 into the foreground
$ fg %3
# Display all information about current jobs
$ jobs —l
# Terminate job 5
$ kill %5
# Increment variable X
$ integer X; ((X+=1))
# Set variable X to 5 in base 2
$ typeset —i2 X=5
# Set variable X to 20 modulo 5
$ ((X=20%5))
# Set Y to 5*4 if X equals 3
$ ((X==3 && (Y=5*4)))
# Terminate the Korn shell if no input given in 30 minutes
$ TMOUT=1800
# Automatically export variables when defined
$ set —o allexport
# Set diagnostic mode
$ set —x
# Create an alias for the ls command
$ alias l='ls —FAc | ${PAGER:—/bin/pg}'
# Create a tracked alias for the cp -r command
$ alias —t "cp —r"
# Put the command number and current directory in the prompt
$ typeset —x PS1="!:$PWD> "
# Check if variable X is set to a number
$ [[$X=+([0-9])]] && print "$X is num"
# Check if X is set to null
$ [[—z $X]] && print "X set to null"
# Check if FILE1 is newer than FILE2
$ [[ $FILE1 —nt $FILE2 ]]
# Check if VAR is set to ABC
$ [[ $VAR = ABC ]]
# Check if the bgnice option is set
$ [[—o bgnice]] && print "bgnice set"
# Check if TMP is a readable directory
$ [[ —d $TMP && —x $TMP ]]
# Check the number of arguments
$(($#==0)) && {print "Need arg"; exit 1;}
# Display an error message, then beep
$ print "Unexpected error!a"
# Display a message on standard error
$ print —u2 "This is going to stderr"
# Write a message to the command history file
$ print —s "su attempted on $(date)"
# Take standard input from FILE
$ exec 0<FILE
# Open file descriptor 5 for reading and writing
$ exec <> 5
# Display a prompt and read the reply into ANSWER
$ read ANSWER?"Enter response: "
# Create a function md that creates a directory and cd's to it
$ function md {mkdir $1 && cd $1 ; pwd}
# Set a trap to ignore signals 2 and 3
$ trap "" 2 3
# Run dbtest in noexec mode
$ ksh —n dbtest
# Set a trap to execute pwd after each command
$ trap "pwd" DEBUG
# Set X to 1 and make it readonly
$ readonly X=1
# Set VAR to 1 and export it
$ export VAR=1
# Set the positional parametersto A B C
$ set A B C
# Set the file size creation limit to 1000 blocks
$ ulimit 1000
# Disable core dumps
$ ulimit —c 0
# Add group write permission to the file creation mask
$ umask 013
# Return information about the true command
$ whence —v true