Best Source of Shell Scripting

What are the best sources for learning and mastering the art of shell scripting ?

There are also some articles on OTN, maybe they're useful to you:
Guide to Advanced Linux Command Mastery Part1
Guide to Advanced Linux Command Mastery Part2
C.

Similar Messages

Finding path to source executed shell script

Hello,
I have shell script A which executes shell script B. The scripts A and B reside in the same directory.
Following requirements:
Scripts A and B need to be source executed.
The directory where A and B resides should be anywhere.
The present working directory from where A is executed should be anywhere.
The directory of scripts A and B may not be defined in $PATH.
The current shell could be any Bourne or Korn shell, Linux or Unix.
Problem:
Let's assume scripts A and B are installed in "/custom".
The users working directory is /home/oracle and he executes "source /custom/A".
If script A executes "source ./B", the result would be "source /home/oracle/B", which will fail.
Possible Solution:
Since script A is being sourced, $0 will always be the name of the current shell and not the name and path to script A.
I have not found a universal solution to locate the absolute path of a shell script that is being source executed.
So I was wondering about defining a variable in script A. e.g. SCRIPT_HOME=./custom. When script A executes "source $SCRIPT_HOME/B" it will work, but then script A needs to be customized by the user.
I could write a script C that edits script A to search and edit the SCRIPT_HOME variable. For this to work I will have to verify that script C is not source executed, and that script A is in the same directory as C based on $0. This is not a problem..
The question however is whether I need to create script C, or could simply execute script A with -config argument to edit itself and exit. I would prefer the later case and from what I understand, Unix and Linux do not lock files by default and this should be possible.
Any comments or suggestions please?
Thanks!
Edited by: Dude on Apr 5, 2011 3:59 AM

The $_ solution is actually very simple:
$ cat thatsme
mypath=$(dirname $_)
echo "$mypath/B"
$ source /home/oracle/thatsme
/home/oracle/BI do not need the absolute path of script A. The relative path from my current directory will do as well.
But, it does not work with an alias:
$ alias thatsme='source /home/oracle/thatsme'
$ thatsme
./B

Shell scripting for oracle DBs

looking for good source for shell scripting for oracle DBs

Just buy 'Classic Shell Scripting' and 'the Unix Desktop Reference' both published by O'Reilly and you have it all.
But if you want a platform agnostic scripting language use Perl. Comes with Oracle.
However both bash and kornshell are a lot easier compared to Perl.
Sybrand Bakker
Senior Oracle DBA

Shell scripts encryption

Hi
We have many shell scripts running on Solaris 9/10 OS. We need to encrypt them so nobody would be able to read them. I tried "Shell guard fstsg", able to create binary executable but execution of binary file fails sometimes. So, thought SHC (shell script compiler) would do for me but getting errors while compiling and install the SHC source code on solaris.
If anyone succeeded installing shc on solaris, please provide me with procedure.
It would be great if i could get SHC binaries for Solaris or any other solution.
Please advise.
Thanks
Prvn

Let me guess - you have passwords embedded in your scripts?
Creating an executable from a shell using some 3rd party tool probably won't give you any protection at all, since the password will still be in "plain text" in the data segment of the executable.
And you obviously cannot execute encrypted code.
Your best bet is to reexamine your authentication policies and use something more secure than a scripted password, like SSH public key authentication.

Avoiding symlink attacks in shell scripts

Hi,
I'm doing a CS course at University and in one of my modules I have to do some shell scripting. For one of the first assignments I have to write a shell script that swaps the contents of two files by moving one to a new temporary location and then swapping them over. I completed this task without any problems, but I had an interesting thought about manipulating files in shell scripts. It seems that it is very common to test to see if a file exists with [ -e filename ] and then proceed on the information gained. However, as every good programmer knows this method is possibly susceptible to at best an annoying bug and at worst a symlink attack, because the operation is not atomic and the file could be created, destroyed, changed to a symlink etc. in between the test and the operation based on that test.
Now I know this is probably overkill for my lame university assignment, but I thought it would be fun to try and find a safe way to do this
In my case, since I am moving to a temporary file I thought it would be good to use the -n option on cp or mv to avoid clobbering the target. Unfortunately, cp/mv still return 0 if the transaction fails due to exisiting file so it takes a bit more work. If you use the -v argument then the utility will print one line of output per file copied/moved, so one solution would be
cp -nv source dest | wc | awk '{print $1}'
which would be 0 if the destination already exists or 1 if one file copied successfully.
Obviously that's a bit long-winded though. Has anyone got a cooler way to do it?

sure you can have race conditions, that's why you should also check if the copy/move/.. completed successfully.
As for the symlink/move different file/.. "attack". this is just a matter of security (eg permissions/ACL's). if you don't want people to mess/put/move/... files you should just use appropriate acl's.

How to call shell script from a pl/sql procedure

Hi all,
I am little bit new to plsql programming, i have a small problem as follows
I have to call a shell script from a pl/sql procedure ..
Please suggest me some methods in oracle 10g, which i could make use of to achieve my goal. also please tell me what are the constraints for those methods if any.
I already came across dbms_scheduler, but i have got a problem and its nor executing properly its exiting giving 255 error or saying that permission problem, but i have already given full access to my shell scripts.
Thanks in advance
Best Regards
Satya

Hi,
Read this thread, perhaps is there your response :
Host...
Nicolas.

Do shell script problem in Applescript

Hi,
I am an Applescript novice and have been trying to write a code to go to a particular folder, look for all files in the folder tree with extension .m2v and run an executable file to decode them. My problem is that when I run my code (containing do shell script), it searches through all files and folders on Mac HD and starts decoding .m2v files elsewhere that I don't want.
Eventually it runs out of space (.m2v file decoding takes a lot of space), because it is dumping all decoded .yuv files onto the HD.
When I run the command on Terminal, it executes the decoding perfectly and stores the decoded files in the same folder.
Please help me about what's going on.
My code is something like:
tell application "Finder"
set DestinationFolder to "xxxxxx:xxxx:xxxx"
set NumFolders to (get count of folders under Destination folder)
repeat for SomeVar from 1 to NumFolders
set FolderinQuestion to folder SomeVar of DestinationFolder
-- Tried tell application "Terminal" here, but did not know --how to export the FolderinQuestion variable from Finder to --Terminal
do shell script " \" cd \" & (POSIX path of (result as text));
for file in `find $pwd \"*.mov\"`
do
/usr/local/bin/decode file
done"
end repeat
end tell
I would greatly appreciate some guidance.

The root of the problem is that you're trying to quote the cd command for some reason:
<pre class=command>do shell script " \" cd \" & (POSIX path of (result as text));
...</pre>
In addition to that you're including the & (POSIX path of (result as text)) as part of the shell command whereas this should be OUTSIDE of the quotes in order to get evaluated
If you work that through you'll end up with a shell command that looks like:
<pre class=command>" cd " & (POSIX path of (result as text))</pre>
If you try to run that in a terminal you'll get a cd : command not found error and that's why the rest of it appears to fail.
The solution to that one is simple - just don't bother quoting the cd and put the POSIX path stuff outside of the quotes to get it evaluated at runtime:
<pre class=command>do shell script "cd " & quoted form of POSIX path of (FolderInQuestion as text)) & ";
# rest of shell commands here"</pre>
Now, as for the rest of the script there are a few things I would change.
First, unless you need to know the index, don't do:
>repeat for SomeVar from 1 to NumFolders
set FolderinQuestion to folder SomeVar of DestinationFolder
the issue is that the number of folders to process may change during the script's execution (other processes may create or remove folders). This will, at best, cause some folders to be skipped and, at worst, cause the script to fail.
If you're iterating through a list, the best option is to just:
<pre class=command>repeat with FolderInQuestion in (folders of DestinationFolder)
...</pre>
This automatically sets the iterator (in this case, FolderInQuestion, to the first item in the list and increments it for each iteration through the loop.
Secondly, in your shell script itself, scrub the entire do/done loop. You're already using find, so have that do the hard work using the -exec switch:
<pre class=command>find path -name "*.mov" -exec /usr/local/bin/decode {} \;</pre>
In find's case, {} is substituted with the current file's path.
Putting this together you'd get:
<pre class=command>tell application "Finder"
set DestinationFolder to "xxxxxx:xxxx:xxxx"
repeat with folderInQuestion in (get folders of folder DestinationFolder)
do shell script "cd " & quoted form of POSIX path of folderInQuestion & "; find . -name \"*.mov\" -exec /usr/bin/decode {} \\;"
end repeat
end tell</pre>
Note that I've used 'quoted form of POSIX path' - this takes care of any shell-unsafe characters like spaces in the path name. I've also used \\; for the -exec switch - this is so that AppleScript passes the \ to the shell command rather than using it for its own escaping.
But you're not done yet!
There's still one fatal flaw in this process - and that is the fact that find by default, is recursive - it will walk through every directory that it finds.
This means that if you start at the top folder and iterate through, find will find all .mov files and decode them. Your script then cd's to the first subdirectory and repeats the process - decoding all the .mov files in that directory and all its subdirectories even though they've ALREADY been decoded.
The upshot is that you only need to run one loop starting at the top level. You don't need to iterate through all the subdirectories since find will do that for you.
In addition to that, there might not be a need to use cd at all since the first argument to find is the directory to start searching in. Unless there's some reason that you need to start decode from the top level directory (e.g. is that where it saves the files?), you can drop the whole repeat loop altogether and just run with:
<pre class=command>set startFolder to (choose folder)
do shell script "find " & quoted form of posix path of startFolder & " -name \"*.mov\" -exec /usr/bin/decode {} \\;"</pre>
That's the entire script - a radical compression of your original.

Problem with backtick replacing apostroph in applescript/shell script

I've got a script that appears to be using a backtick instead of an apostrophe which is causing an error in my shell script. For the life of me I can't seem to find where the error is being generated?
The script is attached below. I'm using Exiftool, an app that writes metadata to image files. The shell script
set cmd to "exiftool -CopyrightNotice=" & exifCopyright & " " & thisFilePath & ""
set theResult to do shell script cmd
works fine but the following shell script
set cmd to "exiftool" & space & authorStr & " " & thisFilePath & ""
set theResult to do shell script cmd
returns the error "sh: -c: line 0: unexpected EOF while looking for matching `''
sh: -c: line 1: syntax error: unexpected end of file" number 2. The code in the event log in applescript editor looks exactly the same to me but one fails in the shell script.
It has been suggested by the developer of Exiftool, Phil Harvey, that there is a backtick in the second shell script. I read somewhere in the applescript docs that this is due to a change in OS 10.6? Any suggestions on how to fix this?
Thanks.
Pedro

Yea, the authorStr value has a space like "Joe Smith"
Then you need to use quoted form of this string, too:
set cmd to "exiftool " & quoted form of authorStr & space & thisFilePath
although the format looks wrong to me - shouldn't there be some kind of switch, such as "-author=' before it?
You have to consider how you'd enter this at the command line to work out how best to translate it to AppleScript. For example, if the command line version were:
exiftool -author='John Doe' /path/to/some.jpg
you can see the quotes are around the name, not the entire -author switch. In this case you should be looking at something like:
set authorStr to "John Doe"
set theFilePath to "/path/to/some.jpg"
set theCmd to "exiftool -author=" & quoted form of authorStr & space & quoted form of theFilePath
Now you could, of course, use quoted form when you create the variables (e.g. set authorStr to quoted form of "John Doe"), but that may screw you up later on if/when you try to use authorStr in some other way, so I find it best to use quoted form only where it's needed.

Catch a value from a pl*sql function in a shell script

Hi all,
I have a shell script that simply calls the following pl*sql function.
echo "execute scott.my_pkg.test('FDLmaster');\n exit;" >./pippo.sql
sqlplus scott/tiger @/fidcap_ftp/FDL/SCRIPTS/pippo.sql
What I have to do to catch the value returned from the function test?
Thanks in advance
best regards
Mario

SQL> create or replace function do_something return varchar2 is
2 begin
3 return ('Something');
4* end;
SQL> /
Function created.
SQL> select do_something from dual;
DO_SOMETHING
Something
SQL> save pippo
Created file pippo.sql
SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.1.0.3.0 - Production
With the Partitioning, OLAP and Data Mining options
[linuxas tmp test10]$ echo exit >>pippo.sql
[linuxas tmp test10]$ VAR=`sqlplus -s scott/tiger @pippo`
[linuxas tmp test10]$ echo $VAR | cut -f3 -d" "
Something
[linuxas tmp test10]$

Problem-Report generation using shell script

Hi
We have the Production database and the Reporting database (copy of Production database),
both on Oracle 9.2.0.5 and Solaris 5.8. There is a package inside the Oracle database, which extracts some data from inside the
database, and would generate a report. A shell script has been created in Solaris which would
send in the parameters and call the pakage to generate the report. The parameters it is sending is
the name of report to be generated, and the location where it is to be generated, both hard-coded into
the script. The script is scheduled to run through crontab.
The problem we are facing is that, if we run the script for Reporting database, it successfully
generates the report. But if we use that script for Production database, it gives the error
"Invalid directory Path". I have tried using various other directory paths, even '/tmp'
and '/', but it still gives the same error when executed for Production dataabse.
Could somebody provide any ideas what might be going wrong.
The reasons it is to be executed on Prod db and not the Reporting database are unavoidable.
It anyway runs in off business hours and takes about 10secs to execute.
Please do let me know if there is any other info that I missed to provide here.
Thanks in advance...

I will be just guessing because you didn't provide contents of script and package.
The "Invalid directory path" as you said could be ORA-29280 due non existent directory.
Try execute (as sys or system) select * from dba_directories; (or select * from all_directories; as user which the script is login to) on both databases and compare the results. If there is missing your important directory then create it using create directory <dirname>; (from sqlplus and don't forget to grant rights for user).
This error could come from shell script. In that case you should find resolution yourself because you didn't provide script source.

How to tell if item is a folder or volume with applescript or shell script?

I am working on a service in Automator that will eject the selected drive when it is finished. Unfortunately automator can only tell the difference between files and folders for the service menu.
Im wondering if if i can use an applescript or shell script that would check if the selected folder is a volume or folder and quit the action if its a folder. I figure the best way to do this is have it determine if the items path is in /Volumes/, but i am completely new to the process and have no idea how to do this.
My automator workflow looks like:
Ask for Confirmation
Get Selected Finder Items
Shell Script
I have the path of the folder selected being passed into the shell script, but after its in there i dont know how to determine if its a volume or not.
Thanks!

K T,
I completely missed that section of the forums, sorry
Neil,
I had that kind of script set up but it was like this:
on run {input, parameters}
tell application "Finder"
kind of item parameters
end tell
end run
And i just figured out that i had to change the first line to "on run {parameters}" and now it works great.
Thanks for the help, it got me going in the right direction

Error in calling SQL plus program with parameter from Shell script

This is my Shell script. I am trying to call in the SQL plus program with the parameter and the shell script is registered as a concurrent program.
PARAMETERS=`echo $1 |tr -d '\"'`
DB_USER_ID=`echo $PARAMETERS|cut -d" " -f3|cut -d"=" -f2`
CONN_STRING=$DB_USER_ID
REQ_DATE=`echo $PARAMETERS|cut -d" " -f9|cut -d"=" -f2`
timestamp=`date +%m-%d-%y-%H:%M:%S-%Z`
timestam=`date +%y-%m-%d`
sqlplus -s $CONN_STRING @ar_statement.sql $REQ_DATE
chmod 755 statement.sh
. statement.sh
My Sql plus program is like this.
set pagesize 0
set heading off
set feedback off
spool $GEC_TOP/log/ge_ar_statement.sh
select output_file_name
from fnd_concurrent_requests
where trunc(actual_completion_date) = '&2';
spool off;
exit;
When i run the concurrent program, i am getting the following error:
ar_statement: line 14: REQ_DATE: command not found
Enter value for 2:
User requested Interrupt or EOF detected.
ar_statement.sh: line 1: Enter: command not found
ar_statement.sh: line 2: User: command not found
ar_statement
Program exited with status 127
I am not strong at Unix Porgamming and i would request someone who can
help me out as soon as possible.
I need this solution quickly and thank everyone in advance.
Thanks.

Can you put your coding between code statements, like shown in the FAQ. It will be easier to read.
Looking at your script, my first guess is that crontab will not find your sqlplus since your script does not have $HOME/bin in the $PATH. From what I understand, running .profile in your script will not work either because variables are exported to sub-shells, not to the shell above. You can call your script with a dot like . ./script which means that the script will run like it was typed at the command prompt. But it will be less confusing to define appropriate variables in the script. eg.
ORACLE_SID=my_instance_name
ORACLE_HOME=/my_path_to_oracle_home_directory
LD_LIBRARY_PATH=$ORACLE_HOME/lib
PATH=$ORACLE_HOME/bin:$PATH
I remember some slightly different way of coding to handle the sqlplus return codes.
For instance:
sqlplus -s /nolog > /dev/null <<-EOF
connect system/manager
@ssm.sql
whenever oserror exit failure
whenever sqlerror exit failure
EOF
sql_err=$?
if [ $sql_err -ne 0 ]; then
echo "FAILURE"
else
echo "SUCCESS"
fiThe - in -EOF supresses tab's
Using connect will prevent ps from showing your login credentials
In some versions of bash the ending EOF needs to be at the beginning of the line to work.
Edited by: waldorfm on Jul 14, 2010 7:05 PM
complaining about putting code between code delimiters and forgot myself ;-)
Edited by: waldorfm on Jul 14, 2010 7:08 PM
Btw, if you "source" a script running it like . .script, than an exit in that script will log you out.

Error while trying to execute a unix shell script from java program

Hi
I have written a program to execute a unix shell script in a remote machine. I am using J2ssh libraries to estabilish the session connection with the remote box.The program is successfully able to connect and authenticate with the box.
The runtime .exec() is been implemented to execute the shell script.I have given below the code snippet.
try {
     File file_location = new File("/usr/bin/");
     String file_location1 = "/opt/app/Hyperion/scripts/daily";
     String a_mib_name = "test.sh";
     String cmd[] = new String[] {"/usr/bin/bash", file_location1, a_mib_name};
     Runtime rtime = Runtime.getRuntime();
     Process p = rtime.exec(cmd, null, file_location);
System.out.println( "Connected to the server1" );
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line = br.readLine();
while(line !=null)
System.out.println(line);
line = br.readLine();
br.close();
p.getErrorStream ().close ();
p.getOutputStream().close();
int retVal = p.waitFor();
System.out.println("wait " + retVal);
//session.executeCommand("ls");
catch (IOException ex) {
I get an error message
Connected to the server
java.io.IOException: Cannot run program "/usr/bin/bash" (in directory "\usr\bin"
): CreateProcess error=3, The system cannot find the path specified
at java.lang.ProcessBuilder.start(Unknown Source)
at java.lang.Runtime.exec(Unknown Source)
at SftpConnect.main(SftpConnect.java:143)
Caused by: java.io.IOException: CreateProcess error=3, The system cannot find th
e path specified
at java.lang.ProcessImpl.create(Native Method)
at java.lang.ProcessImpl.<init>(Unknown Source)
at java.lang.ProcessImpl.start(Unknown Source)
I am sure of the file path where the bash.sh and test.sh are located.
Am i missing something? Any help would be greatly appreciated.
Thanks
Senthil

Hi, I am using a simple program to connect to a RMI server and execute shell script. I use the Runtime.exec aommand to do the same.
The script is sh /tmp/pub/alka/test.sh /tmp/pub/alka/abc/xyz/ul ul
The script when run from the server, gives no errors. But when ran using rthe above method in java, gives errors as follows,
Mycode:
String command = "/bin/sh /tmp/pub/alka/test.sh /tmp/pub/alka/abc/xyz/ul ul";
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec(command);
int exitVal = proc.exitValue();
System.out.println("Process exitValue: " + exitVal);
java.io.IOException: CreateProcess: /bin/sh /tmp/pub/alka/test.sh /tmp/pub/alka/abc/xyz/ul ul error=3
     at java.lang.ProcessImpl.create(Native Method)
     at java.lang.ProcessImpl.<init>(Unknown Source)
     at java.lang.ProcessImpl.start(Unknown Source)
     at java.lang.ProcessBuilder.start(Unknown Source)
     at java.lang.Runtime.exec(Unknown Source)
     at java.lang.Runtime.exec(Unknown Source)
     at java.lang.Runtime.exec(Unknown Source)
     at DecryptTest.main(DecryptTest.java:18)
Can anyone please help

Executing a shell script from pl/sql stored procedure

Hi,
I have Oracle 8i on HP-UX.
I am passing a shell script name as a parameter to a user defined function from a pl/sql stored procedure. This user defined function has insterface to a user defined Java class file in Aurora java virtual machine which is written using runtime class which can execute any OS command or any shell script. I am getting any OS command run successfully, but could not run my own shell script. It's is not getting environment variables of my own, so not getting executed. So please suggest how can get these env variables in my shell script and also suggest other sucurity concerns to be taken into consideration.
If you have any questions please let me know.
This is really a very urgent issue.....
Please help me.
Thanks
Srinivasa Rao Kolla

Your best bet is to use the dbms_pipe builtin package to send the command to the host

Executing a shell script from a jsp page

Hi,
I'm facing a problem while executing a shell script from a jsp page.
I'm using Runtime.exec() function.
It's working fine for single statement scripts.But if the script consists of any database processing and some other processing statements,it's not returning the correct exit status of the process.
Will u please help me in this.
If there is any other ways to execute a shell script from a jsp page other than Runtime.exec() like RMI etc,.If so let me know.
Thanks in advance.

Hello,
It's hard to help you but what you can do is listening to the outputs of your script, you should read the output stream and error stream and send them to the default console.
Check this excellent article : http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html?page=4
Best regards,
Olivier.

Best Source of Shell Scripting

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