Tagged Questions
3
votes
1answer
67 views
Different behavior of $() and `` [duplicate]
% PATH="MYPATH"
% VAR="PATH"
% echo $(eval echo \$$VAR)
MYPATH
% echo `eval echo \$$VAR`
5707VAR
^^
This is the process number.
I thought those two were exactly the same, but obviously there are ...
3
votes
4answers
100 views
Double and triple substitution in bash and zsh
Follow-up to the background part in this question.
In bash I can use {!FOO} for double substitution, in zsh ${(P)FOO}. In both, the old-school (hack-y) eval \$$FOO works.
So, the smartest and most ...
2
votes
2answers
58 views
${!FOO} and zsh
${!FOO} performs a double substitution in bash, meaning it takes the (string) value of FOO and uses it as a variable name.
zsh doesn’t support this feature.
Is there a way to make this work the same ...
2
votes
3answers
253 views
Substitute placeholders in template
Say I have a shell configuration file config like this:
HOST=localhost
PORT=8080
Now I have a template template like this:
The host is <%= @HOST %>
The port is <%= @PORT %>
How do I ...
0
votes
1answer
204 views
Unable to loop through cURL command
I am able to execute individual cURL commands using,
curl -u user:password -v -XPOST -H 'Content-type: text/xml' -d '<featureType><name>quadrella_indica</name></featureType>' ...
0
votes
4answers
188 views
Bash Globbing Variable Substitution? [duplicate]
Possible Duplicate:
Batch renaming files
I want to rename files using their existing name as a base for the new one.
So if I can ls these files with
ls blue*+(.png)
I'd want to rename ...
4
votes
1answer
300 views
Variable substitution with an exclamation mark in bash
I have the following lines in my .cfg bash script file
DDF_SOURCE="siebel_DATA_DATE_FORMAT"
DATA_DATE_FORMAT=${!DDF_SOURCE}
how is ${!DDF_SOURCE} evaluated? It would be !siebel_DATA_DATE_FORMAT, ...
5
votes
3answers
254 views
How to generate new var names on the fly
I'm trying to generate dynamic var names in a shell script to process a set of files with distinct names in a loop as follows:
SAMPLE1='1-first.with.custom.name'
SAMPLE2='2-second.with.custom.name'
...
13
votes
1answer
397 views
Why does variable expansion without $ work in expressions?
#!/bin/bash
VALUE=10
if [[ VALUE -eq 10 ]]
then
echo "Yes"
fi
To my surprise, this outputs "Yes". I would have expected it to require [[ $VALUE -eq 10 ]]. I've scanned the CONDITIONAL ...
2
votes
2answers
255 views
pure shell complex substitution in variable
However it may be impossible, I hope I'm just bad man reader =)
Is there any way to substitute text in variables on several patterns at time or even using back reference?
For example, I have ...
6
votes
2answers
460 views
Dereference concatenated variable name
I can do this, but it requires making a string of the variable then dereferencing it. Is there any way to shorten it to a simpler statement?
#!/bin/bash
FRUITS="BANANA APPLE ORANGE"
...
7
votes
1answer
360 views
Why is bash extended-globbing variable substitution acting at the byte level?
I thought that bash variable substitution and globbing worked at character resolution, so I was rather surprised to see it acting at the byte level.
Everything in my locale is en_AU.UTF-8
When ...
