how to find the real path of folder with regular expression

Question

presto is distributed SQL query engine ,

and when we installed the presto then it should be created the following home folder

/application/DB/presto/presto-server-0.216

so we can say that

in order to capture the home presto we can do ( its part of my bash script )

PRESTO_HOME=` find  /application/DB/presto/ -maxdepth 1 | grep  presto-server `
echo $PRESTO_HOME
/application/DB/presto//presto-server-0.216

BUT ... since some users can rename the folder under /application/DB/presto/ in order to install new version

then under /application/DB/presto , we can get the following folders:

/application/DB/presto/presto-server-HOLD_0.211
/application/DB/presto/_presto-server-0.212
/application/DB/presto/backup_presto-server-0.216.new
/application/DB/presto/presto-server-0.210.old
/application/DB/presto/presto-server-0.212.orig

so regarding that

what is the right syntax in order to find the real path as

/application/DB/presto/presto-server-0.216

notes:

presto folder structure is always with

presto-server-[ any float number or integer number ]

VALID examples:

/application/DB/presto/presto-server-0.736
/application/DB/presto/presto-server-0.936
/application/DB/presto/presto-server-1
/application/DB/presto/presto-server-1.9
/application/DB/presto/presto-server-12

NON VALID examples:

/application/DB/presto/presto-server-0.736-43.previos
/application/DB/presto/presto-server-0.936_old
/application/DB/presto/orig_presto-server-1
/application/DB/presto/presto-server-1.9.bck
/application/DB/presto/presto-server-PREVIOS
/application/DB/presto/presto-server-
/application/DB/presto/presto-server-0.936_old
/application/DB/presto/orig_presto-server-1.other
/application/DB/presto/presto_server-1.9.bck
/application/DB/presto/OLD_presto-server-12-83

Answer 1

Depending on which shell you're using, you could do it with globbing.

bash

#! /bin/bash -
shopt -s nullglob extglob
dirs=(/application/DB/presto/presto-server-+([[:digit:]])*(.+([[:digit:]])))

printf '%s\n' "Found ${#dirs[@]} matching directories:" "${dirs[@]}"

zsh

#! /bin/zsh -
set -o extendedglob
dirs=(/application/DB/presto/presto-server-<->(.<->)#(N))

printf '%s\n' "Found $#dirs matching directories:" $dirs

ksh93

#! /bin/ksh93
dirs=(~(N)/application/DB/presto/presto-server-+([[:digit:]])*(.+([[:digit:]])))

printf '%s\n' "Found ${#dirs[@]} matching directories:" "${dirs[@]}"

For all, that's presto-server- followed by a sequence of 1 or more digits followed by 0 or more sequences of .<digits>.

Answer 2

With GNU find's -regex test, you could use:

find /application/DB/presto/ -regex '/application/DB/presto/presto-server-\([0-9]*\.\)?[0-9]+'

... which requires the leading path, and then the numeric part:

• optionally: leading digits and a period
• one or more digits

That matches all and only your "valid" examples, and none of your "invalid" examples.

Change the [0-9]* to [0-9]+ if you want to require a digit before any leading period; the difference between:

/application/DB/presto/presto-server-0.936

and

/application/DB/presto/presto-server-.936