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From: | Chet Ramey |
Subject: | Re: Bash PS4 and indirection level |
Date: | Tue, 17 Nov 2020 10:02:13 -0500 |
User-agent: | Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 |
On 11/17/20 9:30 AM, Kevin Shell wrote:
On Tue, Nov 17, 2020 at 09:12:52AM -0500, Chet Ramey wrote:On 11/17/20 8:12 AM, Kevin Shell wrote:Hello bash list. What constitutes a level of indirection? The bash manual says the first character of $PS4 indicates one level of indirection but says nothing about what constitutes an indirection level. I found the eval command constitutes one indirection level.Yes, it's essentially a measure of command nesting.Is it mean the command will be processed by the bash lexer/parser one time per indirection level?
More or less. It's one time through the shell equivalent of the read-eval-print loop (read-parse-execute-wait?). -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, UTech, CWRU chet@case.edu http://tiswww.cwru.edu/~chet/
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