Variables don't work that way. Dynamic variable names are discouraged in general -- that's the sort of thing you should be using an array or even just a space-separated string for.
You can dereference a variable name with ${!...} however. (This is a BASH-only feature.)
You must assign the complete variable name to a string first, you can't put substitutions directly inside the ${}.
Struggling to add numbers in shell script..
ie.
a=3
b=4
c=$a + $b
echo $c
I thought this should give me 7 - but cannot see what wrong.. should be simple answer eh? (8 Replies)
Hello all,
Can somebody explain to me how set up a basename and dirname variable to simplify this script. I currently have a 'infile' with the contents of FTTPDataPVC_ & BaaisDSLFeed. I need to add a basename and or dirname variable so that any additions can be made through the infile and not... (1 Reply)
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)
# 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)
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)
Im looking for 2 Files -> *.WAV and *.wav with
find . -name 'unavail.wav' -o -name 'unavail.WAV' I need to list the Folders that contains these 2 Files?
Thx in advance (13 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)
So, let's say I have a usual batch rename file like this:
and I'd like to have a secon bat file, that can /reverse" the first.
BUT, I don't want to simply "rewrite" it like
move hello 254352426
but rather, have the new script take the source and destination and reverse it somehow... (6 Replies)
Discussion started by: pasc
6 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)