How to create a possibly empty array from filename glob?
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With zsh, it is not difficult to create a possibly empty array from the results of a (possibly null) filename glob. For example:
% pathlist=( /no/such/path/*(N) ); printf -- "%dn" $#pathlist
0
With bash, however, the closest approximation I can come up with to the code above fails to produce an empty array when the glob is null:
% pathlist=( /no/such/path/* ); printf -- "%dn" $#pathlist[@] )
1
In this case, the pathlist variable contains a single entry, namely the string "/no/such/path/*".
How can I modify the bash code so that pathlist contains exactly one entry for every file (if any) that matches the glob?
bash scripting wildcards array
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
asked Feb 26 at 22:58
kjo
3,84873358
add a comment |Â
up vote
3
down vote
favorite
With zsh, it is not difficult to create a possibly empty array from the results of a (possibly null) filename glob. For example:
% pathlist=( /no/such/path/*(N) ); printf -- "%dn" $#pathlist
0
With bash, however, the closest approximation I can come up with to the code above fails to produce an empty array when the glob is null:
% pathlist=( /no/such/path/* ); printf -- "%dn" $#pathlist[@] )
1
In this case, the pathlist variable contains a single entry, namely the string "/no/such/path/*".
How can I modify the bash code so that pathlist contains exactly one entry for every file (if any) that matches the glob?
bash scripting wildcards array
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
asked Feb 26 at 22:58
kjo
3,84873358
Possible duplicate of Avoiding errors due to unexpanded asterisk (Chris Down answers your question) or Ignore globs that don't match anything etc...
– don_crissti
Feb 26 at 23:04
1
... and btw, since you're azshuser... thenullgloboption is azshinvention, only added years later tobash
– don_crissti
Feb 26 at 23:14
Comments are not for extended discussion; this conversation has been moved to chat.
– Michael Mrozek♦
Feb 27 at 17:36
add a comment |Â
up vote
3
down vote
favorite
up vote
3
down vote
favorite
With zsh, it is not difficult to create a possibly empty array from the results of a (possibly null) filename glob. For example:
% pathlist=( /no/such/path/*(N) ); printf -- "%dn" $#pathlist
0
With bash, however, the closest approximation I can come up with to the code above fails to produce an empty array when the glob is null:
% pathlist=( /no/such/path/* ); printf -- "%dn" $#pathlist[@] )
1
In this case, the pathlist variable contains a single entry, namely the string "/no/such/path/*".
How can I modify the bash code so that pathlist contains exactly one entry for every file (if any) that matches the glob?
bash scripting wildcards array
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
asked Feb 26 at 22:58
kjo
3,84873358
With zsh, it is not difficult to create a possibly empty array from the results of a (possibly null) filename glob. For example:
% pathlist=( /no/such/path/*(N) ); printf -- "%dn" $#pathlist
0
With bash, however, the closest approximation I can come up with to the code above fails to produce an empty array when the glob is null:
% pathlist=( /no/such/path/* ); printf -- "%dn" $#pathlist[@] )
1
In this case, the pathlist variable contains a single entry, namely the string "/no/such/path/*".
How can I modify the bash code so that pathlist contains exactly one entry for every file (if any) that matches the glob?
bash scripting wildcards array
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
asked Feb 26 at 22:58
kjo
3,84873358
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
edited Feb 27 at 0:32
Jeff Schaller
31.2k846105
31.2k846105
asked Feb 26 at 22:58
kjo
3,84873358
asked Feb 26 at 22:58
kjo
3,84873358
asked Feb 26 at 22:58
kjo
3,84873358
3,84873358
Possible duplicate of Avoiding errors due to unexpanded asterisk (Chris Down answers your question) or Ignore globs that don't match anything etc...
– don_crissti
Feb 26 at 23:04
1
... and btw, since you're azshuser... thenullgloboption is azshinvention, only added years later tobash
– don_crissti
Feb 26 at 23:14
Comments are not for extended discussion; this conversation has been moved to chat.
– Michael Mrozek♦
Feb 27 at 17:36
add a comment |Â
Possible duplicate of Avoiding errors due to unexpanded asterisk (Chris Down answers your question) or Ignore globs that don't match anything etc...
– don_crissti
Feb 26 at 23:04
1
... and btw, since you're azshuser... thenullgloboption is azshinvention, only added years later tobash
– don_crissti
Feb 26 at 23:14
Comments are not for extended discussion; this conversation has been moved to chat.
– Michael Mrozek♦
Feb 27 at 17:36
Possible duplicate of Avoiding errors due to unexpanded asterisk (Chris Down answers your question) or Ignore globs that don't match anything etc...
– don_crissti
Feb 26 at 23:04
Possible duplicate of Avoiding errors due to unexpanded asterisk (Chris Down answers your question) or Ignore globs that don't match anything etc...
– don_crissti
Feb 26 at 23:04
1
1
... and btw, since you're a
zsh user... the nullglob option is a zsh invention, only added years later to bash– don_crissti
Feb 26 at 23:14
... and btw, since you're a
zsh user... the nullglob option is a zsh invention, only added years later to bash– don_crissti
Feb 26 at 23:14
Comments are not for extended discussion; this conversation has been moved to chat.
– Michael Mrozek♦
Feb 27 at 17:36
Comments are not for extended discussion; this conversation has been moved to chat.
– Michael Mrozek♦
Feb 27 at 17:36
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
7
down vote
accepted
You need to use the shell option nullglob
#!/bin/bash
shopt -s nullglob
pathlist=( /no/such/path/* ); printf -- "%dn" "$#pathlist[@]" )
shopt -u nullglob
The Bash manual says the following about the nullglob shell option:
If set, Bash allows filename patterns which match no files to expand to a null string, rather than themselves.
answered Feb 26 at 23:01
Jesse_b
10.4k22658
2
notedeclare -p pathlistis a nice way to dump an array variable.
– glenn jackman
Feb 26 at 23:30
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simplyecho "$#pathlist[@]"
– Jesse_b
Feb 27 at 0:09
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
7
down vote
accepted
You need to use the shell option nullglob
#!/bin/bash
shopt -s nullglob
pathlist=( /no/such/path/* ); printf -- "%dn" "$#pathlist[@]" )
shopt -u nullglob
The Bash manual says the following about the nullglob shell option:
If set, Bash allows filename patterns which match no files to expand to a null string, rather than themselves.
answered Feb 26 at 23:01
Jesse_b
10.4k22658
2
notedeclare -p pathlistis a nice way to dump an array variable.
– glenn jackman
Feb 26 at 23:30
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simplyecho "$#pathlist[@]"
– Jesse_b
Feb 27 at 0:09
add a comment |Â
up vote
7
down vote
accepted
You need to use the shell option nullglob
#!/bin/bash
shopt -s nullglob
pathlist=( /no/such/path/* ); printf -- "%dn" "$#pathlist[@]" )
shopt -u nullglob
The Bash manual says the following about the nullglob shell option:
If set, Bash allows filename patterns which match no files to expand to a null string, rather than themselves.
answered Feb 26 at 23:01
Jesse_b
10.4k22658
2
notedeclare -p pathlistis a nice way to dump an array variable.
– glenn jackman
Feb 26 at 23:30
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simplyecho "$#pathlist[@]"
– Jesse_b
Feb 27 at 0:09
add a comment |Â
up vote
7
down vote
accepted
up vote
7
down vote
accepted
You need to use the shell option nullglob
#!/bin/bash
shopt -s nullglob
pathlist=( /no/such/path/* ); printf -- "%dn" "$#pathlist[@]" )
shopt -u nullglob
The Bash manual says the following about the nullglob shell option:
If set, Bash allows filename patterns which match no files to expand to a null string, rather than themselves.
answered Feb 26 at 23:01
Jesse_b
10.4k22658
You need to use the shell option nullglob
#!/bin/bash
shopt -s nullglob
pathlist=( /no/such/path/* ); printf -- "%dn" "$#pathlist[@]" )
shopt -u nullglob
The Bash manual says the following about the nullglob shell option:
If set, Bash allows filename patterns which match no files to expand to a null string, rather than themselves.
answered Feb 26 at 23:01
Jesse_b
10.4k22658
edited Feb 27 at 0:10
answered Feb 26 at 23:01
Jesse_b
10.4k22658
answered Feb 26 at 23:01
Jesse_b
10.4k22658
answered Feb 26 at 23:01
Jesse_b
10.4k22658
10.4k22658
2
notedeclare -p pathlistis a nice way to dump an array variable.
– glenn jackman
Feb 26 at 23:30
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simplyecho "$#pathlist[@]"
– Jesse_b
Feb 27 at 0:09
add a comment |Â
2
notedeclare -p pathlistis a nice way to dump an array variable.
– glenn jackman
Feb 26 at 23:30
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simplyecho "$#pathlist[@]"
– Jesse_b
Feb 27 at 0:09
2
2
note
declare -p pathlist is a nice way to dump an array variable.– glenn jackman
Feb 26 at 23:30
note
declare -p pathlist is a nice way to dump an array variable.– glenn jackman
Feb 26 at 23:30
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
@glennjackman: Where would that fit into the answer?
– Jesse_b
Feb 26 at 23:35
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
Instead of the printf...
– Jeff Schaller
Feb 26 at 23:56
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simply
echo "$#pathlist[@]"– Jesse_b
Feb 27 at 0:09
OP is using printf to simply print the number of elements in the array though, not a declare statement for it...If anything it would be better written as simply
echo "$#pathlist[@]"– Jesse_b
Feb 27 at 0:09
add a comment |Â
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Possible duplicate of Avoiding errors due to unexpanded asterisk (Chris Down answers your question) or Ignore globs that don't match anything etc...
– don_crissti
Feb 26 at 23:04
1
... and btw, since you're a
zshuser... thenullgloboption is azshinvention, only added years later tobash– don_crissti
Feb 26 at 23:14
Comments are not for extended discussion; this conversation has been moved to chat.
– Michael Mrozek♦
Feb 27 at 17:36