Shell Programming and Scripting

It seems to me that putting the output from all of the cmd* scripts in a single file is just making your life harder (since you have to manually find the end of each command file's output and write it to a separate file to mail it back to the user), but I have done as you requested. I did sneak in two status lines in the output.txt file that should make it easier to separate the output after all of the cmd* files have finished and have also included the exit code in the closing separator line in output.txt since I would think your users will want that information.

This script logs when a script starts, when it ends (and includes its exit status), and when the last script ends to the file log.txt. Both log.txt and output.txt are cleared when you start this script; so don't run it a second time before you extract all of the data you need from output.txt. This seems dangerous to me, but it is what you requested.

Code:

#!/bin/bash
# Throw away output from previous runs.
> output.txt

# Redirect this script's output to log file.
exec > log.txt 2>&1

# Loop through all available cmd scripts.
i=1
while [ -f cmd$i ]
do      date "+cmd$i starting @ %c"
        date "+================ cmd$i start ================ %c" >> output.txt
        sh cmd$i >> output.txt 2>&1
        ec=$?
        date "+============= cmd$i exit code $ec ============= %c" >> output.txt
        date "+cmd$i exit code $ec @ %c" >> log.txt
        i=$((i + 1))
done
date "+Scripts finished @ %c"

Thank you very much sir !!!
I will try this when I get in the office on Thursday.

Have a nice weekend.

The script works great.
I am just trying to figure out the script.

"exec > log.txt 2>&1"
what is the function of exec , shows all output of everything being executed?
"do date "+cmd$i starting @ %c" "
how does the script know how to send this to the log.txt?
what is "ec=$? "

i=$((i + 1))
this tells the scripts to restart the commands but with the next cmd file?

Thx.

The general format for the exec command:

Code:

    exec command [redirections]

overlays the current shell script with the command named by command and performs the input and/or output redirections specified by redirections for that command. When no command is specified, the exec command performs the specified redirections for the current script. So, in this case:

Code:

exec > log.txt 2>&1

no command is specified, so the standard output of the remaining commands in this script that do not otherwise redirect their standard output will be written to the file named log.txt and any data written to standard error by the remaining commands in this script that do not otherwise redirect their standard error output will be sent to the same file. Since the redirection to log.txt uses ">" (rather than ">>"), data in log.txt (if there is any) will be discarded before continuing with the following commands.
That is what the exec command above did.
The shell variable $? is the exit status of the previous command. It is being saved in the variable ec because I need to use the value in the next two commands.
This increments the value of the shell variable i as the last of the commands in the while loop:

Code:

while condition
do      commands
done

After incrementing i, [ -f cmd$i ] (the condition in this while loop) tests whether or not there is a regular file named cmdx where x is the current value of the shell variable i? If cmdx does exist, the commands in the loop are executed again with the updated value of i.