[digiology2]

Hi, I've just been messing about and I tried to make a shell script that will give me the full name of the present day, it doesn't work though. on wednesdy it outputs wedday. That means add2 isn't getting changed to 'nes'
I know its probably not the best way of doing it but Im just trying to learn.
Any thoughts?



#!/bin/sh
#makes a new message everyday

set `uptime`
echo "Your system has been running for $3 minutes"

set `date`
if test $1=Mon || test $1=Fri || test $1=Sun
then
add2=

elif test $1=Tue
then
add2=s

elif test $1=Thu
then
add2=rs

elif test $1=Wed
then
add2+=nes

else
add2=er


fi

add=day

echo "Today is $1$add2$add"

[Mithras]

hmm, i don't think there's a += operator.
Try add2=${add2}nes

also, it's more conventional to use [ ] instead of the word 'test' in shell scripts.

[digiology2]

Thanks, I forgot to take the += out of the code before i posted it. I was just testing it out.
Anyone know where I can get examples of more simple shell scripts?

Mithras, do you mean I can replace 'test' with '[]' ?

[digiology2]

That didn't work. The problem isn't with the wednesday statement, its with the whole structure, the line 'add2=nes' isn't even being executed. Otherwise it would have realised the += mistake. Instead it outputted wedday ie leaving add2 blank.

Cheers

[Arkham_c]

Code:
day_of_the_week=`date +"%a"`

case $day_of_the_week in
Mon)
    real_day="Monday"
;;
Tue)
    real_day="Tuesday"
;;
Wed)
    real_day="Wednesday"
;;
Thu)
    real_day="Thursday"
;;
Fri)
    real_day="Friday"
;;
Sat)
    real_day="Saturday"
;;
Sun)
    real_day="Sunday"
;;
esac

echo "Today is $real_day"

[Mithras]

Or, if brevity is the goal:
echo "Today is `date '+%A'`"


Here's a good little guide that I used a bunch in first learning bash scripting:
http://pegasus.rutgers.edu/~elflord/unix/bash-tute.html

and this is the definitive guide:
http://www.tldp.org/LDP/abs/html/

[digiology2]

thanks Arkham_c, but the synthax is completely different to what I know. I wanted to do it the complex way and have different sections of the string/word.
Im unfamiliar with
;;
Tue)

for example.
Is there anyway of fixing what I have done?

[digiology2]

also, what is %a ?

[Arkham_c]

Originally posted by digiology2:
thanks Arkham_c, but the synthax is completely different to what I know. I wanted to do it the complex way and have different sections of the string/word.
Im unfamiliar with
;;
Tue)

for example.
Is there anyway of fixing what I have done?

also, what is %a ?

Yes, you can fix what you did. As an earlier poster mentioned, nobody calls test like that. Here it is, in the form most like what you did, but syntactically, correct:

Code:
#!/bin/sh

today=`date +"%a"`
if [ "${today}" = "Mon" ] || [ "${today}" = "Fri" ] || [ "${today}" = "Sun" ]; then
    add2=""
elif [ "${today}" = "Tue" ]; then
    add2="s"
elif [ "${today}" = "Thu" ]; then
    add2="rs"
elif [ "${today}" = "Wed" ]; then
    add2="nes"
else # Saturday
    add2="ur"
fi

add="day"
echo "Today is ${today}${add2}${add}"

the "[ ]" syntax is running "test" without calling it by name. It is the generally accepted way of calling test, and is easier to read too.

The "+%a" is a strftime format string for the date command. If you read the man page for strftime, you'll see:

Code:
     %A    is replaced by national representation of the full weekday name.
     %a    is replaced by national representation of the abbreviated weekday
           name.

There are a ton of formatting options you can pass to date to customize what it prints.

Just for the sake of completeness, here is how I would modify my earlier example using case statements to do the "complex" solution:

Code:
#!/bin/sh

today=`date +"%a"`

case $today in
Mon|Fri|Sun)
    add2=""
;;
Tue)
    add2="s"
;;
Wed)
    add2="nes"
;;
Thu)
    add2="rs"
;;
else)
    add2="ur"
;;
esac

add="day"
echo "Today is ${today}${add2}${add}"

[digiology2]

Thank you! I'll be back at the unix forum again to annoy you all when I do another script!

[digiology2]

sorry, what is strftime? You said that '+%a' is part of the strftime command (although it doesn't seem to act like a command, ie i wasn't able to use it in the terminal), but you don't use strftime in the script (the one done my way but fixed).

Please explain, thanks.

I'd like to do it with the few commands I know and it appears you are doing so but i still don't get %a

[Arkham_c]

Originally posted by digiology2:
sorry, what is strftime? You said that '+%a' is part of the strftime command (although it doesn't seem to act like a command, ie i wasn't able to use it in the terminal), but you don't use strftime in the script (the one done my way but fixed).

Please explain, thanks.

I'd like to do it with the few commands I know and it appears you are doing so but i still don't get %a

strftime is a function in the "C" programming language. It is used universally in C programs to format time values into a human-readable string. The "date" command uses strftime internally to format the time in "date". The default format for date is "%a %b %e %H:%M:%S %Z %Y".

If you open a Terminal and type "man strftime" you'll see all the formatting options for strftime. You can use any of these with the command-line "date" command as follows:

date +"format"

where format is a strftime format string.

[digiology2]

but it appears %a, %b ect is the same as refering to $1, $2 ect after using the set command.

I suppose its just a different way of doing things.

How would I apply a command to every visible (ie when 'ls' is typed) file in a folder, I know you can use while loops but is there some way of counting all the files in the current folder so I can control the while loop with another variable ie

while -variable- <= -amount of files in folder-
{do command on file -variable-
increase variable by one}

or in a more java like synthax:

count=0;
while (count <= filecount)
{
command
count++
}


I'm just curious how to apply a command in every file in the folder it doesn't have to involve a counter cariable or a while loop for that matter.

Cheers

[Arkham_c]

Originally posted by digiology2:
I'm just curious how to apply a command in every file in the folder it doesn't have to involve a counter cariable or a while loop for that matter.

This is how I do it:

Code:
for file in `ls`; do
    # do something with $file here
done