Actually it is the first two bytes and they inform the OS' program loader that the file is a script and that the remainder of the line specifies which command interpreter to run, with the script name as argument.
In addition it might be worth adding that only absolute pathes are allowed here. This:
will work, whereas
will not, even if ../../something would correctly resolve to the executable.
I am using an array (clmlist01). I have 61 of these and have 4 or more references to each one in a block of code that I do not want to have to hardcode. With that being said, I am creating a varible and going through a for loop to create the actually name of each array. The arrays would end up... (3 Replies)
I am facing a strange error while creating posix threads:
Given below are two snippets of code, the first one works whereas the second one gives a garbage value in the output.
Snippet 1
This works:
--------------
int *threadids;
threadids = (int *) malloc (num_threads * sizeof(int));
... (4 Replies)
Hello,
Please tell me if there is a better way to get the number of elements from an array that is passed to a function.
This is what works on Solaris 8 (ksh) but it looks odd:
loop_array() {
array_name=$2
b1='\${\#'
b2='}'
nr_elements=`eval echo... (6 Replies)
Hi,
What is the actual difference between these two? Why the following code works for process substitution and fails for command substitution?
while IFS= read -r line; do echo $line; done < <(cat file)executes successfully and display the contents of the file
But,
while IFS='\n' read -r... (3 Replies)
I've created a series of arrays named as follows:
row1
row2
row3
.
.
.
row10
Each has 4 elements.
I'm trying to echo the array elements out in a for loop. Here's what I have:
for ((i=1;i<=10;i++))
do
for ((j=1;j<=4;j++))
do
eval out=${row`echo $i`}
echo -n $out (3 Replies)
Hi.
I´ve a script that should substitude the 8th line in a file called xxx.num6.
The "xxx" is set by an array filled with this command:
j=0
for Par in *.sys ; do
Par=`echo $Par | sed 's/\(.*\).sys/\1/'` ;
Par2="$Par" ; echo "${Par2}"
j=$((j + 1));
done
Now i try... (0 Replies)
I have an array and two variables as below,
I need to check if $datevar is present in $filename.
If so, i need to replace $filename with the values in the array.
I need the output inside an ARRAY
How can this be done.
Any help will be appreciated. Thanks in advance. (2 Replies)
Trying to do some control flow parsing based on the index postion of an array member. Here is the pseudo code I am trying to write in (preferably in pure bash) where possible. I am thinking regex with do the trick, but need a little help.
pesudo code
if == ENDSINFIVEINTS ]]; then
do... (4 Replies)
Hi folks,
A really dumb question as I've wasted far too long trying to get this to work.... (on RH bash)
I have an array:
m0='<hello>'
m0='<there>'
m0='<fred>'
v0='<goodbye>'
v0='<again>'
v0='<john>'
in my code I calculate the value of the variable to output and if I echo it, I... (2 Replies)
hello,
i need a bit of help on how to do this effectively in bash without a lot of extra looping or massive switch/case
i have a long array of M elements and a short array of N elements, so M > N always. M is not a multiple of N.
for case 1, I want to stretch N to fit M
arrayHuge
H = (... (2 Replies)
Discussion started by: f77hack
2 Replies
LEARN ABOUT MOJAVE
catch
catch(n) Tcl Built-In Commands catch(n)
__________________________________________________________________________________________________________________________________________________NAME
catch - Evaluate script and trap exceptional returns
SYNOPSIS
catch script ?resultVarName? ?optionsVarName?
_________________________________________________________________DESCRIPTION
The catch command may be used to prevent errors from aborting command interpretation. The catch command calls the Tcl interpreter recur-
sively to execute script, and always returns without raising an error, regardless of any errors that might occur while executing script.
If script raises an error, catch will return a non-zero integer value corresponding to the exceptional return code returned by evaluation
of script. Tcl defines the normal return code from script evaluation to be zero (0), or TCL_OK. Tcl also defines four exceptional return
codes: 1 (TCL_ERROR), 2 (TCL_RETURN), 3 (TCL_BREAK), and 4 (TCL_CONTINUE). Errors during evaluation of a script are indicated by a return
code of TCL_ERROR. The other exceptional return codes are returned by the return, break, and continue commands and in other special situa-
tions as documented. Tcl packages can define new commands that return other integer values as return codes as well, and scripts that make
use of the return -code command can also have return codes other than the five defined by Tcl.
If the resultVarName argument is given, then the variable it names is set to the result of the script evaluation. When the return code
from the script is 1 (TCL_ERROR), the value stored in resultVarName is an error message. When the return code from the script is 0
(TCL_OK), the value stored in resultVarName is the value returned from script.
If the optionsVarName argument is given, then the variable it names is set to a dictionary of return options returned by evaluation of |
script. Tcl specifies two entries that are always defined in the dictionary: -code and -level. When the return code from evaluation of |
script is not TCL_RETURN, the value of the -level entry will be 0, and the value of the -code entry will be the same as the return code. |
Only when the return code is TCL_RETURN will the values of the -level and -code entries be something else, as further described in the doc- |
umentation for the return command. |
When the return code from evaluation of script is TCL_ERROR, three additional entries are defined in the dictionary of return options |
stored in optionsVarName: -errorinfo, -errorcode, and -errorline. The value of the -errorinfo entry is a formatted stack trace containing |
more information about the context in which the error happened. The formatted stack trace is meant to be read by a person. The value of |
the -errorcode entry is additional information about the error stored as a list. The -errorcode value is meant to be further processed by |
programs, and may not be particularly readable by people. The value of the -errorline entry is an integer indicating which line of script |
was being evaluated when the error occurred. The values of the -errorinfo and -errorcode entries of the most recent error are also avail- |
able as values of the global variables ::errorInfo and ::errorCode respectively. |
Tcl packages may provide commands that set other entries in the dictionary of return options, and the return command may be used by scripts |
to set return options in addition to those defined above.
EXAMPLES
The catch command may be used in an if to branch based on the success of a script.
if { [catch {open $someFile w} fid] } {
puts stderr "Could not open $someFile for writing
$fid"
exit 1
}
There are more complex examples of catch usage in the documentation for the return command.
SEE ALSO
break(n), continue(n), dict(n), error(n), return(n), tclvars(n)
KEYWORDS
catch, error
Tcl 8.5 catch(n)