Display calendar in correct format using shell script

Shell Programming and Scripting
1

Hi All,

I'm trying to print calendar using shell script and i'm able to print it. But the format is not good.

Here is the script.

#!/bin/bash
echo $(date)
echo "Hello $USER"
echo Hostname $(hostname)
echo Working in $(pwd)
echo Here is this month calender
echo $(cal)

[cracha@cs ~]$ sh first.sh
Mon Sep 22 12:37:42 IST 2014
Hello cracha
Hostname cs
Working in /home/cracha
Here is this month calender
September 2014 Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
[cracha@cs ~]$

Please let me know how to print it in right format.

Regards,
Chandu

2

Hello Chandrakanth,

Welcome to forum, kindly use code tags while posting commands and codes in post. Following may help you in same.

#!/bin/bash
echo "hello" `whoami`
echo `hostname`
echo `pwd`
echo "Here is the calender for this month"
cal

Thanks,
R. Singh

3

You have some unnecessary echo commands and command substitutions.
Try the following instead:

#!/bin/bash
date
echo "Hello $USER"
echo "Hostname $(hostname)"
echo "Working in $PWD"
echo "Here is this month's calendar"
cal
4

Thanks Both,

Both the codes worked for me.
Can you guys help me understand when to use "" and ' ' and $() ?
Or direct me to a link that explains these.

(I'm new to linux and shell scripting)

Thanks in advance.

Regards,
Chandu

5

$(..) is the syntax that replaced ` command something ` the result is the execution of the code between the braces..
For the quotes and double quotes its best you experience with them and you tell us what you understood: e.g.

n12:/home/vbe/wks/test $ TITI=01
n12:/home/vbe/wks/test $ echo "$TITI"
01
n12:/home/vbe/wks/test $ echo '$TITI' 
$TITI

So?

6

So "" is used to print the value of a variable.

Regards,
Chandu

7

Is this a homework assignment?

If you don't know what $(cal) does, why did you use it in your script?

If you use echo $(cal) with command substitution and no quotes, all of the sequences of whitespace characters will be converted by the shell into single spaces before being passed to echo . The text between single quotes will be treated by the shell unchanged as a single operand. The text between double quotes will be treated by the shell as a single operand after performing variable expansions, arithmetic expansions, and command substitutions. Compare the results from the following commands:

printf '%s\n' $PWD $(cal)
printf '%s\n' "$PWD" "$(cal)"
printf '%s\n' '$PWD' '$(cal)'
8

Hi Don,

This is not a Homework assignment. I just started learning shell programming.

Thanks for your inputs.

Regards,
Chandu