The && and || operators are not a replacement for a proper if - else - fi block".
While one can use subshells, as you did, to do additional tasks if a false has returned, being a subshell, you cannot exit from there, as it just exits the subshell, not the script.
Now try:
Check if of the if blocks exit status, by executing:
After you ran the script.
hth
EDIT:
Simply said, the && and || operators are only good for SIMPLE checks, not for complex checking.
MAinly because one cannot use multiple instances of ||, if ANY previous condition fails, it'll go to the first ||, and be done after.
Hi ,
I have a situation.
Need is to create & send a formatted file with header in BOLD & colored & some sequel results as a content.
I know echo -e \033 command, but its scope is limited in PUTTY.
How to retain the formatting out of Putty; say after someone opens a email attachment... (2 Replies)
Dear unix gurus,
I have a data file with header information about a subject and also 3 columns of n rows of data on various items he owns. The data file looks something like this:
adam peter
blah blah blah
blah blah blah
car
01 30 200
02 31 400
03 57 121
.. .. ..
.. .. ..
n y... (8 Replies)
Hi friends,
I have a script that sets the env variable path based on different conditions.
Now the new path variable setting should not done in the same terminal or same shell.
Only a new terminal or new shell should have the new path env variable set.
I am able to do this only as follows:
>cd... (1 Reply)
find . -type f -name "*.sql" -print|xargs perl -i -pe 's/pattern/replaced/g'
this is simple logic to find and replace in multiple files & folders
Hope this helps.
Thanks
Zaheer (0 Replies)
Hi, I hope the title does not scare people to look into this thread but it describes roughly what I'm trying to do. I need a solution in PHP.
I'm a programming beginner, so it might be that the approach to solve this, might be easier to solve with an other approach of someone else, so if you... (0 Replies)
Hello All
I have a xml file with many sets of records
like this
<mytag>mydata</mytag>
<tag2>data&</tag2>
also same file can be like this
<mytag>mydata</mytag>
<tag2>data&</tag2>
<tag3>data2&data3</tag3>
Now i can grep & and replace with & for whole file but it will replace all... (4 Replies)
Hi, I have text file abc.txt. In this file, I have the following data.
Input:
Mr Smith & Mrs Smith
Mr Smith &apos Mrs Smith
Mr Smith & Mrs Smith
Mr Smith& Mrs Smith
Mr Smith &Mrs Smith
Output:
Mr Smith & Mrs Smith
Mr Smith &apos Mrs Smith
Mr Smith & Mrs Smith
Mr Smith&... (4 Replies)
cat file1.txt
field1 "user1":
field2:"data-cde"
field3:"data-pqr"
field4:"data-mno"
field1 "user1":
field2:"data-dcb"
field3:"data-mxz"
field4:"data-zul"
field1 "user2":
field2:"data-cqz"
field3:"data-xoq"
field4:"data-pos"
Now i need to have the date like below.
i have just... (7 Replies)
Firstly, I would like to apologize if this is not the appropriate sub-forum to post about GNU/BSD makefile scripting. Though my code is in C++, because I am focusing on the makefile I thought it would go better in shell scripting. Please correct me if I am wrong.
Secondly, I am not interested in... (0 Replies)
Hi All,
Do you have any sample script,
- auto get file from SFTP remote server and delete file in remove server after downloaded.
- only download specify filename
- auto upload file from local to SFTP remote server and delete local folder file after uploaded
- only upload specify filename
... (3 Replies)
Discussion started by: weesiong
3 Replies
LEARN ABOUT X11R4
wait
wait(1) User Commands wait(1)NAME
wait - await process completion
SYNOPSIS
/bin/sh
wait [pid...]
/bin/jsh /bin/ksh /usr/xpg4/bin/sh
wait [pid...]
wait [ % jobid...]
/bin/csh
wait
DESCRIPTION
The shell itself executes wait, without creating a new process. If you get the error message cannot fork,too many processes, try using the
wait command to clean up your background processes. If this doesn't help, the system process table is probably full or you have too many
active foreground processes. There is a limit to the number of process IDs associated with your login, and to the number the system can
keep track of.
Not all the processes of a pipeline with three or more stages are children of the shell, and thus cannot be waited for.
/bin/sh, /bin/jsh
Wait for your background process whose process ID is pid and report its termination status. If pid is omitted, all your shell's currently
active background processes are waited for and the return code will be 0. The wait utility accepts a job identifier, when Job Control is
enabled (jsh), and the argument, jobid, is preceded by a percent sign (%).
If pid is not an active process ID, the wait utility will return immediately and the return code will be 0.
csh
Wait for your background processes.
ksh
When an asynchronous list is started by the shell, the process ID of the last command in each element of the asynchronous list becomes
known in the current shell execution environment.
If the wait utility is invoked with no operands, it will wait until all process IDs known to the invoking shell have terminated and exit
with an exit status of 0.
If one or more pid or jobid operands are specified that represent known process IDs (or jobids), the wait utility will wait until all of
them have terminated. If one or more pid or jobid operands are specified that represent unknown process IDs (or jobids), wait will treat
them as if they were known process IDs (or jobids) that exited with exit status 127. The exit status returned by the wait utility will be
the exit status of the process requested by the last pid or jobid operand.
The known process IDs are applicable only for invocations of wait in the current shell execution environment.
OPERANDS
The following operands are supported:
One of the following:
pid The unsigned decimal integer process ID of a command, for which the utility is to wait for the termination.
jobid A job control job ID that identifies a background process group to be waited for. The job control job ID notation is applicable
only for invocations of wait in the current shell execution environment, and only on systems supporting the job control option.
USAGE
On most implementations, wait is a shell built-in. If it is called in a subshell or separate utility execution environment, such as one of
the following,
(wait)
nohup wait ...
find . -exec wait ... ;
it will return immediately because there will be no known process IDs to wait for in those environments.
EXAMPLES
Example 1: Using A Script To Identify The Termination Signal
Although the exact value used when a process is terminated by a signal is unspecified, if it is known that a signal terminated a process, a
script can still reliably figure out which signal is using kill, as shown by the following (/bin/ksh and /usr/xpg4/bin/sh):
sleep 1000&
pid=$!
kill -kill $pid
wait $pid
echo $pid was terminated by a SIG$(kill -l $(($?-128))) signal.
Example 2: Returning The Exit Status Of A Process
If the following sequence of commands is run in less than 31 seconds (/bin/ksh and /usr/xpg4/bin/sh):
sleep 257 | sleep 31 &
jobs -l %%
then either of the following commands will return the exit status of the second sleep in the pipeline:
wait <pid of sleep 31>
wait %%
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of wait: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), jobs(1), ksh(1), sh(1), attributes(5), environ(5), standards(5)SunOS 5.10 12 Dec 1997 wait(1)