using while loop to run till the number is postive ie <!= 0
If I understand you correctly what you want is to increment a number until it reaches above 0?
but the code you offered as your attempt will only loop in the while "$a" is already greater than or equal to 0:
Then since "$a" is instantiated as 0 and it matches the first while condition you start incrementing "$a":
after that increment you are testing if "$a" is less than or equal to 0 and break out of the while loop if it is:
Essentially you do this:
1. Set $a = 0
2. Test is $a is equal or grater than zero
3. Increment $a by 1 (making it now $a=1)
4. Test for it to be 0 or less and break if it is
5. echo $a
6. Restart while loops with $a equal to 1
This will never break as $a will always be 0 or greater which means it will evaluate to true in the while condition and then it will just echo numbers to screen growing by 1 each time forever (or until you manually kill it).
Try this instead:
Now obviously we could just have easily placed a break inside that if statement instead of increment $a. The point was to show a valid way to break if $a is not 0 though.
Hi,
For my bash script, terminal with bash is generate an OK output and program works right.
already,
terminal with ash have "line 48: syntax error: Bad substitution" output and program don't work.
:confused: (0 Replies)
Hi All,
I need to pass a variable to perl script from bash script, where in perl i am using if condition. Here is the cmd what i am using in perl
FROM_DATE="06/05/2008"
TO_DATE="07/05/2008"
"perl -ne ' print if ( $_ >="$FROM_DATE" && $_ <= "$TO_DATE" ) ' filename"
filename has... (10 Replies)
hi,
i have a script that runs on bash and would like to run it on a machine that has csh and bash. the default setting on that machine is csh. i dont want to change my code to run it with a csh shell. is there any way i can run the script (written in bash) on this machine? in other words is there... (3 Replies)
Hey guys, i'm having trouble complete one of my bash scripts
I'm hoping to ---
1. Modify bash so that then the user types "ls" the command that is executed is "ls -al"
2. Modify the point of entry in bash when the user accesses it, moving the initial location to /var
I've somewhat done #2,... (9 Replies)
Hi everybody,
Lets say, I have two bash scripts named down.sh and up.sh located in two different folders named ~/home/a/ and ~/home/b/
Now I want to write another bash script, located in ~/home/ which runs these other two scripts, so that I only have to execute this one comprehensive script... (1 Reply)
# check host value regex='^(||1|2|25)(\.(||1|2|25)){3}$' if ')" != "" ]; then if ]; then echo host $host not found exit 4 fi elif ]; then echo $host is an invalid host address exit 5 fi
espeacailly the top regex part?
---------- Post updated at 06:58 PM ---------- Previous update was... (1 Reply)
I want to give my long scripts to customer. The customer must not be able to read the scripts even if he has the password. The following command locks and unlocks the script but the set +x is simply ignored.
The code:
read -p 'Script: ' S && C=$S.crypt H='eval "$((dd if=$0 bs=1 skip=//|gpg... (7 Replies)
So I'm trying to pass certain json elements as env vars and use them later on in a script.
Sample json:
JSON='{
"Element1": "file-123456",
"Element2": "Name, of, company written in, a very weird way",
"Element3": "path/to/some/file.txt",
}'
(part of the) script:
for s... (5 Replies)
I'm new to utilities like socat and netcat and I'm not clear if they will do what I need.
I have a "compileDeployStartWebServer.sh" script and a "StartBrowser.sh" script that are started by emacs/elisp at the same time in two different processes.
I'm using Cygwin bash on Windows 10.
My... (3 Replies)
In Bash shell - the ps -ef shows only the /bin/bash but the script name is not displayed ? Is there any way to get the script names for the process command ?
--- Post updated at 08:39 AM ---
in KSH (Korn Shell), my command output shows the script names but when run in the Bash Shell... (3 Replies)
Discussion started by: i4ismail
3 Replies
LEARN ABOUT OPENDARWIN
after
after(n) Tcl Built-In Commands after(n)
__________________________________________________________________________________________________________________________________________________NAME
after - Execute a command after a time delay
SYNOPSIS
after ms
after ms ?script script script ...?
after cancel id
after cancel script script script ...
after idle ?script script script ...?
after info ?id?
_________________________________________________________________DESCRIPTION
This command is used to delay execution of the program or to execute a command in background sometime in the future. It has several forms,
depending on the first argument to the command:
after ms
Ms must be an integer giving a time in milliseconds. The command sleeps for ms milliseconds and then returns. While the command is
sleeping the application does not respond to events.
after ms ?script script script ...?
In this form the command returns immediately, but it arranges for a Tcl command to be executed ms milliseconds later as an event
handler. The command will be executed exactly once, at the given time. The delayed command is formed by concatenating all the
script arguments in the same fashion as the concat command. The command will be executed at global level (outside the context of
any Tcl procedure). If an error occurs while executing the delayed command then the bgerror mechanism is used to report the error.
The after command returns an identifier that can be used to cancel the delayed command using after cancel.
after cancel id
Cancels the execution of a delayed command that was previously scheduled. Id indicates which command should be canceled; it must
have been the return value from a previous after command. If the command given by id has already been executed then the after can-
cel command has no effect.
after cancel script script ...
This command also cancels the execution of a delayed command. The script arguments are concatenated together with space separators
(just as in the concat command). If there is a pending command that matches the string, it is cancelled and will never be executed;
if no such command is currently pending then the after cancel command has no effect.
after idle script ?script script ...?
Concatenates the script arguments together with space separators (just as in the concat command), and arranges for the resulting
script to be evaluated later as an idle callback. The script will be run exactly once, the next time the event loop is entered and
there are no events to process. The command returns an identifier that can be used to cancel the delayed command using after can-
cel. If an error occurs while executing the script then the bgerror mechanism is used to report the error.
after info ?id?
This command returns information about existing event handlers. If no id argument is supplied, the command returns a list of the
identifiers for all existing event handlers created by the after command for this interpreter. If id is supplied, it specifies an
existing handler; id must have been the return value from some previous call to after and it must not have triggered yet or been
cancelled. In this case the command returns a list with two elements. The first element of the list is the script associated with
id, and the second element is either idle or timer to indicate what kind of event handler it is.
The after ms and after idle forms of the command assume that the application is event driven: the delayed commands will not be executed
unless the application enters the event loop. In applications that are not normally event-driven, such as tclsh, the event loop can be
entered with the vwait and update commands.
SEE ALSO
bgerror(n), concat(n), update(n), vwait(n)
KEYWORDS
cancel, delay, idle callback, sleep, time
Tcl 7.5 after(n)