The user knows to call the script with either 1 or 2 command arguments. Depending on the call I need the script to perform different operations. How exactly would I check if the second command argument is null?
In a script , i would like to check if the argument ( $1, $2 inside the script) contain wildcard (*,? etc). how do i do it?
> script_name arg1 arg*
$1 (arg1) does not contain wildcard, but $2 (arg* )contains wildcard. how can i tell in script?
i need to do this is because :
if arg1... (3 Replies)
Here is the command in question for f in $(<uploads); do .
I only want this to execute if uploads is not empty. If uploads is empty I want the script to quit, actually before the for command. If its not apparent uploads is a text file.
Chris (3 Replies)
Hello All,
I have written shell script whcih at the max 3 parameters.
When only one commandline argument and other two command line arguments are passed as empty string like
eg : archive ' ' ' '
Then i need to check whether the commandline... (12 Replies)
How do I check if a file is empty in a sh script
I want to test in my shell script if the output file is empty and if it is do one thing and if it isnt empty do another?
any ideas? (8 Replies)
I have the list of users in user.log, under each user folder there is sub1 folder is there. i want to check whether sub1 is empty or not, if it is empty i have to skip that user user folder and iterate next user folders. i have the sample code,its not giving not proper results.
while read line... (8 Replies)
I need to check if a directory is empty using an if condition
in the pseudocode below
if ; then
else
although i looked at a few forums on this topic, I left feeling a little unclear and i could not use the command successfully
what can i substitute in the if conditon above,... (2 Replies)
If ($argv == “-debug”) then
Echo “in loop”
Endif
But this is not working. If I modify this code and remove “-“, then it works.
Similarly I am getting problem using grep command also
Grep “-debug” Filename
Can someone please help me on how to resolve these... (1 Reply)
hi,
i want to check whether a a variable contains some value or is empty in a shell script. so if the variable contains some value i want to do some job and if the variable doesnt contain any value then i need to skip that job.
here is a sample script
read_filenames.sh contains
... (5 Replies)
All,
I'm writing an argument checking block and running into an error. I want to confirm that $1 is one of two values. Here is what I have:
if ]; then
echo -e "\nPlease check your first augument. You used \"$1\"
which is not recognized. Please see usage:"
usage
... (9 Replies)
Hello
So i have that script collection, in which i have a single script to create a configuration file.
In there, i have multiple occourences of something like this:
prj_title=$(tui-read "What is the TITLE? ($prj_name):")
] && prj_title="${prj_name/_/ }"
They all work as expected, if... (5 Replies)
Discussion started by: sea
5 Replies
LEARN ABOUT REDHAT
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)