i was studying about variable substitution. below are info which was given in a online tutorial.
in order to understand its functinality i write a small script mentioned as below.
here i am not able to understand the use of
and
and why it is taking initial value of parameter which is "two" in last 2 cases.
Hey All,
I'm trying to clean up a variable using sed but It dosn't seem to work. I'm trying to find all the spaces and replace them with "\ " (a slash and a space). For Example "Hello World" should become "Hello\ World". But it does nothing. If I put it directly into the command line it works... (3 Replies)
Hi everyone,
I have a simple question to ask :
In a script that I'm writting, I need to create variables on-the-fly.
For instance, for every iterartion of the following loop a var_X variable should be generated :
#!/bin/ksh
a="1 2 3"
for i in $a
do
var_${i}=$i
echo "${var_$i}"
done
... (1 Reply)
I have run into a wall with my iptables firewall scripting.
I am blocking all of the private side IP addresses on the
WAN interface on systems running NAT. However, if the
system is not running NAT and needs to allow access to
the local LAN on the WAN interface, I need to block all
but one of... (2 Replies)
Hello,
i have another sed question.. I'm trying to do variable substition with sed and i'm running into a problem.
my var1 is a string constructed like this:
filename1 filerev1 filepath1
my var2 is another string constructed like this:
filename2 filerev2 filepath2
when i do... (2 Replies)
Hi,
That might be pretty simple.
How can I generate a variable name and get their value ?
Thanks a lot.
Something like:
>CUSTOMER_NF=26
> object=CUSTOMER
> echo ${object}_NF
CUSTOMER_NF
> echo ${${object}_NF}
ksh: ${${object}_NF}: 0403-011 The specified substitution is... (7 Replies)
Hi,
I am facing a strange problem. I have a script that used the following to search and replace text:
sed 's/'"${find_var_parm}"'/'"${find_var_filter}"'/g' $ParmFile > $TempFile
The values of $find_var_parm and $find_var_filter are set based on search criteria. The above seems to be working... (2 Replies)
Hi ,
I have a variable as follows,
Temp=`cat ABC.txt | cut -c5-`
This will yeild a part of the date. say , 200912.
I would like to substitute this variable's value in a filename.
eg: File200912F.zip
when i say File$TempF.zip , it is not substituting.
Any help ?
Thanks in... (2 Replies)
For example I have variable like below
echo $OUTPUT
/some/path/`uname -n`
when I try to use the variable OUTPUT like below
cd $OUTPUT or cd ${OUTPUT}
I am getting bad substituion error message
$ cd $OUTPUT
ksh: cd: bad substitution
$ cd ${OUTPUT}
ksh: cd: bad substitution
... (1 Reply)
Hi,
I have to write a shell script in which I have to substitute a variable within a variable. For example,
var1=aaa
var2=file.$var1.txt
The output should be,
echo $var2
file.aaa.txt
Can someone please help me in getting this. I tried using eval, but it didnt work. I might be using it... (2 Replies)
Hi
I am having a file like this
##############################
j=1
while ]
do
temp_5=MODULE$j
awk '
$1 ~ /'${!temp_5}'/ {
do something }1' file1 > file2
((j = j +1 ))
done ###################
Setting the variables like this (8 Replies)
Discussion started by: kshitij
8 Replies
LEARN ABOUT MOJAVE
subst
subst(n) Tcl Built-In Commands subst(n)
__________________________________________________________________________________________________________________________________________________NAME
subst - Perform backslash, command, and variable substitutions
SYNOPSIS
subst ?-nobackslashes? ?-nocommands? ?-novariables? string
_________________________________________________________________DESCRIPTION
This command performs variable substitutions, command substitutions, and backslash substitutions on its string argument and returns the
fully-substituted result. The substitutions are performed in exactly the same way as for Tcl commands. As a result, the string argument
is actually substituted twice, once by the Tcl parser in the usual fashion for Tcl commands, and again by the subst command.
If any of the -nobackslashes, -nocommands, or -novariables are specified, then the corresponding substitutions are not performed. For
example, if -nocommands is specified, command substitution is not performed: open and close brackets are treated as ordinary characters
with no special interpretation.
Note that the substitution of one kind can include substitution of other kinds. For example, even when the -novariables option is speci-
fied, command substitution is performed without restriction. This means that any variable substitution necessary to complete the command
substitution will still take place. Likewise, any command substitution necessary to complete a variable substitution will take place, even
when -nocommands is specified. See the EXAMPLES below.
If an error occurs during substitution, then subst will return that error. If a break exception occurs during command or variable substi-
tution, the result of the whole substitution will be the string (as substituted) up to the start of the substitution that raised the excep-
tion. If a continue exception occurs during the evaluation of a command or variable substitution, an empty string will be substituted for
that entire command or variable substitution (as long as it is well-formed Tcl.) If a return exception occurs, or any other return code is
returned during command or variable substitution, then the returned value is substituted for that substitution. See the EXAMPLES below.
In this way, all exceptional return codes are "caught" by subst. The subst command itself will either return an error, or will complete
successfully.
EXAMPLES
When it performs its substitutions, subst does not give any special treatment to double quotes or curly braces (except within command sub-
stitutions) so the script
set a 44
subst {xyz {$a}}
returns "xyz {44}", not "xyz {$a}" and the script
set a "p} q {r"
subst {xyz {$a}}
returns "xyz {p} q {r}", not "xyz {p} q {r}".
When command substitution is performed, it includes any variable substitution necessary to evaluate the script.
set a 44
subst -novariables {$a [format $a]}
returns "$a 44", not "$a $a". Similarly, when variable substitution is performed, it includes any command substitution necessary to
retrieve the value of the variable.
proc b {} {return c}
array set a {c c [b] tricky}
subst -nocommands {[b] $a([b])}
returns "[b] c", not "[b] tricky".
The continue and break exceptions allow command substitutions to prevent substitution of the rest of the command substitution and the rest
of string respectively, giving script authors more options when processing text using subst. For example, the script
subst {abc,[break],def}
returns "abc,", not "abc,,def" and the script
subst {abc,[continue;expr {1+2}],def}
returns "abc,,def", not "abc,3,def".
Other exceptional return codes substitute the returned value
subst {abc,[return foo;expr {1+2}],def}
returns "abc,foo,def", not "abc,3,def" and
subst {abc,[return -code 10 foo;expr {1+2}],def}
also returns "abc,foo,def", not "abc,3,def".
SEE ALSO
Tcl(n), eval(n), break(n), continue(n)
KEYWORDS
backslash substitution, command substitution, variable substitution
Tcl 7.4 subst(n)