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Count Characters, Lines and Words
$wc [ –clw ] [ files ]
Description:
The wc command counts the characters, lines, or words in the specified files. A total count for all files is kept.
Options:
| –c | display number of characters (default all options) |
| –l | display number of lines |
| –w | display number of words |
| files | read standard input if no files are specified |
# Execute multiple commands on one line
$ pwd ; ls tmp ; echo "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
$ 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
# Send the standard error of xsend to stderr.out
$ xsend file 2>stderr.out
# 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]
# Set NU to the number of users that are logged on
$ NU=`who | wc -l`
# Set TOTAL to the sum of 4 + 3
$ TOTAL=`expr 4 + 3`
# Set and export the variable LBIN
$ LBIN=/usr/lbin; export LBIN
# Unset variable LBIN
$ unset LBIN
# Set SYS to the hostname if not set, then display its value
$ echo ${SYS:=`uuname -l`}
# Display an error message if XBIN is not set
$ : ${XBIN:?}
# Display $HOME set to /home/anatole
$ echo '$HOME set to' $HOME
# Display the value of $TERM
$ echo $TERM
# Bring background job 3 into the foreground
$ fg %3
# Stop the find job
$ stop %find
# Display the number of positional parameters
$ echo "There are $# positional parameters"
# Display the value of positional parameter 2
$ echo $2
# Display all information about current jobs
$ jobs -l
# Terminate job 5
$ kill %5
# Increment variable X
$ X=`expr $X + 1`
# Set variable X to 20 modulo 5
$ X=`expr 20 % 5`
# Set diagnostic mode
$ set -x
# Run the dbscript in noexec mode
$ sh -n dbscript
# Check for new mail every 2 minutes
$ MAILCHECK=120; export MAILCHECK
# Set the primary prompt string
$ PS1='Good morning!'; export PS1
# Check if VAR is set to null
$ [-z "$VAR"] && echo "VAR is set to null"
# Check if VAR is set to ABC
$ ["$VAR" = ABC ]
# Check if xfile is empty
$ test ! -s xfile
# Check if tmp is a directory
$ [ -d tmp ]
# Check if file is readable and writable
$ test -r file -a -w file
# Display an error message, then beep
$ echo "Unexpected error!\007"
# Display a message on standard error
$ echo "This is going to stderr" >&2
# Display a prompt and read the reply into ANSWER
$ echo "Enter response: \c"; read ANSWER
# Create a function md that creates a directory and cd's to it
$ md() { mkdir $1 && cd $1 ; pwd ; }
# Set a trap to ignore signals 2 and 3
$ trap "" 2 3
# Set X to 1 and make it readonly
$ X=1 ; readonly X
# Set VAR to 1 and export it
$ VAR=1 ; export VAR
# Set the positional parameters to 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
# Display the first and third fields from file
$ awk '{print $1, $3}' file
# Display the first seven characters of each line in tfile
$ cut –c1–7 tfile
# Display the first and third fields from the /etc/passwd file
$ cut –f1,3 –d":" /etc/passwd
# Display lines in names that begin with A, B, C, or Z
$ egrep '[A–C,Z]*' names
# Display lines from dict that contain four character words
$ egrep '....' dict
# Display password entries for users with the Korn shell
$ grep ":/bin/ksh$' /etc/passwd
# Display number of lines in ufile that contain unix; ignore case
$ grep –c 'unix' ufile
# Display the lengths of field 1 from file
$ nawk'{TMP=length($1);print $TMP}' file
# Display the first ten lines of tfile
$ nawk '{for (i=1; i<10; i++) \
printf "%s\n", getline}' tfile
# List the contents of the current directory in three columns
$ ls | paste d" " – – –
# Display file with all occurrences of The substituted with A
$ sed 's/The/A/g' file
# Display your user name only
$ id | sed 's/).*//' | sed 's/.*(//'
# Display file with lines that contain unix deleted
$ sed '/unix/d' file
# Display the first 50 lines of file
$ sed 75q file
# Sort the /etc/passwd file by group id
$ sort -t":" -n +3 -4 /etc/passwd
# Translate lower case letters in file to upper case
$ cat file | tr a-z A-Z
# Display adjacent duplicate lines in file
$ uniq –d file
# Display the numbers of characters and words in file
$ wc –l file
# Display the number of .c files in the current directory
$ ls *.c | wc -l
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