When you invoke a script
you can enter whatever arguments you want, whether the script likes it or not.
This script will tell you if the number of arguments you gave it is not equal to 1
First it sets envame = parameter #1
Then it tests to see if the envanme variable is "empty". If the variable is empty the script print a message
showing the correct usage of the script, then exits with error status.
FWIW the correct way to do this in modern POSIX shells is:
Hello,
I've got a problem with SED. It's my intention to shorten a file path (removing the file name) with the help of SED. Something like:
tmp\folder1\folder2\blah.txt has to be transformed to
tmp\folder1\folder2\.
I suppose, it's on the tip of my tongue. Perhaps it's close to:
sed... (2 Replies)
Hi,
I have the following file:
--#
--#line1
--#line2
--#line3
--#
--#line4
--#line5
and I want to use something like:
sed 's/--#/newline/g' file > newfile
to substitute the lines containing only '--#', but when I try, it replaces every instance of '--#' with 'newline' and I... (7 Replies)
Hi!
I'm having problems to get this simple script done:
I need to insert 50 lines with the value from the variable dtm=`date +"%d"` into a new file, how do I do that using the "for" or "while" loop commands ? Is there any other command I can use to do that ? I'm new to shell scripting, as you can... (8 Replies)
I am not that good with AWK. Is there a simple awk command I could use to get the word "this" from the following text besides using "awk -F ":" '{print $2} | awk -F " " '{print $1}"?
:this is:that is: (6 Replies)
how do I alias the following command:
ls -l |egrep 'drw|dr-|d--|d-w'
The alias command needs single quotes and so does the above command, so this does not work:
alias LSDIR 'ls -l |egrep 'drw|dr-|d--|d-w' '
My problem is how do I get a listing of only directories?
Solaris 8
SUN Ultra 10... (4 Replies)
I am currently having a problem with displaying multiple occurences of a line using grep/sed combination. Let's say that I do grep "$anything" $file.
When I do this it only displays a single line, but if I do grep -c "$anything" $file it says that there are 3 occurences of $anything, but how can... (15 Replies)
Hi everyone I'm new here and I don't know some command of unix, please help by describe me how it work, I study unix command by myself and can't search exactly means so...Thanks :D
sqlplus -s /nolog @${SQLFILE} ${file_type} >> ${OUTPUT_FILE}
date "+%Y%m%d%H%M%S"
$/usr/bin/echo "INFO : $1"... (2 Replies)
Hi there,
given the file
FIELD1 FIELD2 FIELD3 FIELD4 FIELD5 FIELD6 FIELD7 FIELD8 FIELD9 FIELD10 FIELD11
Why does not
awk '$6 == "FIELD6" {$6=="GREEN"}1' file
do the work and replace"FIELD6" by "GREEN"?
And second question, what is the purpose of the "1" at the end of... (5 Replies)
Discussion started by: la2015
5 Replies
LEARN ABOUT REDHAT
catch
catch(n) Tcl Built-In Commands catch(n)
__________________________________________________________________________________________________________________________________________________NAME
catch - Evaluate script and trap exceptional returns
SYNOPSIS
catch script ?varName?
_________________________________________________________________DESCRIPTION
The catch command may be used to prevent errors from aborting command interpretation. Catch calls the Tcl interpreter recursively to exe-
cute 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 one of the exceptional return codes (see tcl.h for
the definitions of code values). If the varName argument is given, then the variable it names is set to the error message from interpret-
ing script.
If script does not raise an error, catch will return 0 (TCL_OK) and set the variable to the value returned from script.
Note that catch catches all exceptions, including those generated by break and continue as well as errors. The only errors that are not
caught are syntax errors found when the script is compiled. This is because the catch command only catches errors during runtime. When
the catch statement is compiled, the script is compiled as well and any syntax errors will generate a Tcl error.
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
}
The catch command will not catch compiled syntax errors. The first time proc foo is called, the body will be compiled and a Tcl error will
be generated.
proc foo {} {
catch {expr {1 +- }}
}
KEYWORDS
catch, error
Tcl 8.0 catch(n)