EVERY command that returns non-zero gets routed into the trap. Example: when you are using grep to test a string and it fails, you end up in the trap. So, you will have to have a global variable that holds the error text so the trap can ignore most harmless non-zero returns
This User Gave Thanks to jim mcnamara For This Post:
Hi I want to implement the nice command in the shell that I am building. I came to know that there is a corresponding nice() system call for the same. But since I will be forking different processes to run different commands typed on the command prompt, is there any way I can make a command... (2 Replies)
Hi folks,
I have tried to add some trap detection in the below script....this script is used to monitor database activities...in a rather awkward way :rolleyes:....
The idea behind adding trap is that....this script creates lots of temporary files in the running folder to store the count... (1 Reply)
I have a rather simple routine that I would like to fine tune. I am having scripters block if that exists. Trying to tally up that amount of subnets after I performed an awk and uniq from zipped apache logs. For instance, on a solaris 10 system:
This does work
gunzip -c access_log1.200834.gz |... (2 Replies)
Hey all UNIX nerds- I've built a shell script which runs pretty well- only I want it to have much better error trapping. (Like the kind I could apply to every shell script I write).
I'm not a UNIX genius, and could really use a bit of help.
The original script goes something like this:
1... (3 Replies)
I have another Question:
I tried to run the following script: (I actually wanted to print out the second field in the text field.)
#!/usr/bin/ksh
set -x
readfile=/dir1/data.txt
cat $readfile | while read line
do
x = `echo $line|awk '{print $2}'`
echo $x
done
But, it shows the... (3 Replies)
I have a script that prompts the user for a response. How can I use the trap command to capture the question ask and the users response to a log file?
Thanks in advance,:D (1 Reply)
Hello,
I am just starting with shell scripting, as everyone will soon see from my question. What I'm trying to do is call the Nice command to set the script process priority from /bin/ksh. The difference is I'm running it not directly through the shell, but through Bigfix (very similar to... (3 Replies)
Dear Members,
I have a table in Oracle DB and one of its column name is INFO which has data in text format which we need to fetch in a script and create an xml file of a new table from the input.
The contents of a single cell of INFO column is like:
Area:app - aam
Clean Up Criteria:... (0 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
That is the last reply I received from my instructor, and I'm looking for some alternatives.
When using... (2 Replies)
sqlplus -s usrname/password@dbSID <<-SQL >> logfile
@create_table.sql
commit;
quit;
SQL
I am running this script to execute an sql file.
I want to display the oracle error if anything found during execution of the sql file and exit from script.
Please suggest How do it. (1 Reply)
Discussion started by: millan
1 Replies
LEARN ABOUT DEBIAN
trap
trap(1) User Commands trap(1)NAME
trap, onintr - shell built-in functions to respond to (hardware) signals
SYNOPSIS
sh
trap [ argument n [n2...]]
csh
onintr [-| label]
ksh
*trap [ arg sig [ sig2...]]
DESCRIPTION
sh
The trap command argument is to be read and executed when the shell receives numeric or symbolic signal(s) (n). (Note: argument is scanned
once when the trap is set and once when the trap is taken.) Trap commands are executed in order of signal number or corresponding symbolic
names. Any attempt to set a trap on a signal that was ignored on entry to the current shell is ineffective. An attempt to trap on signal 11
(memory fault) produces an error. If argument is absent all trap(s) n are reset to their original values. If argument is the null string
this signal is ignored by the shell and by the commands it invokes. If n is 0 the command argument is executed on exit from the shell. The
trap command with no arguments prints a list of commands associated with each signal number.
csh
onintr controls the action of the shell on interrupts. With no arguments, onintr restores the default action of the shell on interrupts.
(The shell terminates shell scripts and returns to the terminal command input level). With the - argument, the shell ignores all inter-
rupts. With a label argument, the shell executes a goto label when an interrupt is received or a child process terminates because it was
interrupted.
ksh
trap uses arg as a command to be read and executed when the shell receives signal(s) sig. (Note that arg is scanned once when the trap is
set and once when the trap is taken.) Each sig can be given as a number or as the name of the signal. trap commands are executed in order
of signal number. Any attempt to set a trap on a signal that was ignored on entry to the current shell is ineffective. If arg is omitted
or is -, then the trap(s) for each sig are reset to their original values. If arg is the null (the empty string, e.g., "" ) string then
this signal is ignored by the shell and by the commands it invokes. If sig is ERR then arg will be executed whenever a command has a non-
zero exit status. If sig is DEBUG then arg will be executed after each command. If sig is 0 or EXIT for a trap set outside any function
then the command arg is executed on exit from the shell. The trap command with no arguments prints a list of commands associated with each
signal number.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), exit(1), ksh(1), sh(1), attributes(5)SunOS 5.10 23 Oct 1994 trap(1)