Re: [CentOS] Special characters in bash strings
On Wed, Jul 06, 2022 at 09:41:14PM -0400, H wrote:
I have run into a bash variable string problem that I think I have nailed down
to the variable string containing a tilde (~). Not sure if my conclusion is
correct and could use some help.
To make a long(er) story short, an associative array variable was created:
p[work_path]="~/projects/test/"
and referenced in the following format in the shell script:
"${p[work_path]}"
Is there a reason you desire "delayed" evaluation of the tilde?
If no, then evaluate the tilde in the above assignment by not
quoting it.
If yes, then where tilde evaluation IS wanted, you will likely
need to do a second round of shell evaluation of the command
line by using the keyword "eval".
$ x="~/foo"
$ y=~"/foo" # y contains the tilde evaluated version
$ echo "$x $y"
~/foo /home/jon/foo
$ echo $x $y# quotes don't matter here
~/foo /home/jon/foo
$ eval echo "$x $y"
/home/jon/foo /home/jon/foo
Use of eval could introduce other unexpected/unwanted
evaluations and is discouraged unless required.
--
Jon H. LaBadie j...@labadie.us
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Re: [CentOS] Special characters in bash strings
On 7/6/22 18:41, H wrote: To my consternation this worked fine in some places but not in others. It might be easier to explain if you had an example of where it worked. The bash man page has a section titled "EXPANSION" that details the order in which expansions happen. Since tilde expansion happens before variable expansion, the case you're discussing shouldn't work in any context (other than an eval or equivalent). ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] Special characters in bash strings
I have run into a bash variable string problem that I think I have nailed down
to the variable string containing a tilde (~). Not sure if my conclusion is
correct and could use some help.
To make a long(er) story short, an associative array variable was created:
p[work_path]="~/projects/test/"
and referenced in the following format in the shell script:
"${p[work_path]}"
To my consternation this worked fine in some places but not in others. I tried
to use the above construct when piping output, as part of a file reference when
calling psql from the command line and when referencing an xslt file with
xsltproc.
In some places it worked, in others it did not but when I substituted the
variable reference above with the path in clear text itself it then worked.
It looks like there are some nuances on variable substitution that I have yet
to learn, perhaps tied to the use of the tilde since using the variable
p[work_path]="/home/user/projects/test/" seemed to work in all places.
Pointers welcome!
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