Can't append to array from a while loop [duplicate]
This question already has an answer here:
How to pipe input to a Bash while loop and preserve variables after loop ends
2 answers
While-loop subshell dilemma in Bash
3 answers
I want to get all the filenames in a folder, filter them, and put them all in an array.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
find $folder -name "*.flac" | while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done
print ${list[@]}
The problem is that appending to the array while inside the loop, as shown above, does nothing. Outside the loop it works fine.
I am able to access the filename variable inside the loop and have confirmed that it is what it should be and non-empty.
The file names have spaces and some have UTF-8 characters, for all that it matters.
shell ksh
asked Dec 29 '18 at 18:30
NickNick
11
marked as duplicate by Charles Duffy shell
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Dec 29 '18 at 19:23
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
This question already has an answer here:
How to pipe input to a Bash while loop and preserve variables after loop ends
2 answers
While-loop subshell dilemma in Bash
3 answers
I want to get all the filenames in a folder, filter them, and put them all in an array.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
find $folder -name "*.flac" | while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done
print ${list[@]}
The problem is that appending to the array while inside the loop, as shown above, does nothing. Outside the loop it works fine.
I am able to access the filename variable inside the loop and have confirmed that it is what it should be and non-empty.
The file names have spaces and some have UTF-8 characters, for all that it matters.
shell ksh
asked Dec 29 '18 at 18:30
NickNick
11
marked as duplicate by Charles Duffy shell
Users with the shell badge can single-handedly close shell questions as duplicates and reopen them as needed.
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Dec 29 '18 at 19:23
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
This is BashFAQ #24.
– Charles Duffy
Dec 29 '18 at 19:23
add a comment |
This question already has an answer here:
How to pipe input to a Bash while loop and preserve variables after loop ends
2 answers
While-loop subshell dilemma in Bash
3 answers
I want to get all the filenames in a folder, filter them, and put them all in an array.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
find $folder -name "*.flac" | while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done
print ${list[@]}
The problem is that appending to the array while inside the loop, as shown above, does nothing. Outside the loop it works fine.
I am able to access the filename variable inside the loop and have confirmed that it is what it should be and non-empty.
The file names have spaces and some have UTF-8 characters, for all that it matters.
shell ksh
asked Dec 29 '18 at 18:30
NickNick
11
This question already has an answer here:
How to pipe input to a Bash while loop and preserve variables after loop ends
2 answers
While-loop subshell dilemma in Bash
3 answers
I want to get all the filenames in a folder, filter them, and put them all in an array.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
find $folder -name "*.flac" | while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done
print ${list[@]}
The problem is that appending to the array while inside the loop, as shown above, does nothing. Outside the loop it works fine.
I am able to access the filename variable inside the loop and have confirmed that it is what it should be and non-empty.
The file names have spaces and some have UTF-8 characters, for all that it matters.
This question already has an answer here:
How to pipe input to a Bash while loop and preserve variables after loop ends
2 answers
While-loop subshell dilemma in Bash
3 answers
shell ksh
shell ksh
asked Dec 29 '18 at 18:30
NickNick
11
asked Dec 29 '18 at 18:30
NickNick
11
edited Dec 29 '18 at 18:59
Nick
asked Dec 29 '18 at 18:30
NickNick
11
asked Dec 29 '18 at 18:30
NickNick
11
asked Dec 29 '18 at 18:30
NickNick
11
11
marked as duplicate by Charles Duffy shell
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Dec 29 '18 at 19:23
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
marked as duplicate by Charles Duffy shell
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Dec 29 '18 at 19:23
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
This is BashFAQ #24.
– Charles Duffy
Dec 29 '18 at 19:23
add a comment |
This is BashFAQ #24.
– Charles Duffy
Dec 29 '18 at 19:23
This is BashFAQ #24.
– Charles Duffy
Dec 29 '18 at 19:23
This is BashFAQ #24.
– Charles Duffy
Dec 29 '18 at 19:23
add a comment |
1 Answer
1
active
oldest
votes
Looks like the while loop was run in a subshell, as such it was in a different scope. This fixes it.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done <<< $(find $folder -name "*.flac")
print ${list[@]}
https://www.gnu.org/software/bash/manual/bashref.html#Here-Strings
answered Dec 29 '18 at 19:11
NickNick
11
This code is quite unsafe -- needs more quotes (find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.
– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put/etc/passwdin the list of results.
– Charles Duffy
Dec 29 '18 at 19:25
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0)is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).
– Charles Duffy
Dec 29 '18 at 19:26
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Looks like the while loop was run in a subshell, as such it was in a different scope. This fixes it.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done <<< $(find $folder -name "*.flac")
print ${list[@]}
https://www.gnu.org/software/bash/manual/bashref.html#Here-Strings
answered Dec 29 '18 at 19:11
NickNick
11
This code is quite unsafe -- needs more quotes (find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.
– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put/etc/passwdin the list of results.
– Charles Duffy
Dec 29 '18 at 19:25
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0)is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).
– Charles Duffy
Dec 29 '18 at 19:26
add a comment |
Looks like the while loop was run in a subshell, as such it was in a different scope. This fixes it.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done <<< $(find $folder -name "*.flac")
print ${list[@]}
https://www.gnu.org/software/bash/manual/bashref.html#Here-Strings
answered Dec 29 '18 at 19:11
NickNick
11
This code is quite unsafe -- needs more quotes (find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.
– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put/etc/passwdin the list of results.
– Charles Duffy
Dec 29 '18 at 19:25
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0)is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).
– Charles Duffy
Dec 29 '18 at 19:26
add a comment |
Looks like the while loop was run in a subshell, as such it was in a different scope. This fixes it.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done <<< $(find $folder -name "*.flac")
print ${list[@]}
https://www.gnu.org/software/bash/manual/bashref.html#Here-Strings
answered Dec 29 '18 at 19:11
NickNick
11
Looks like the while loop was run in a subshell, as such it was in a different scope. This fixes it.
#!/bin/mksh
folder="/home/jj/Music/DOWNLOADS"
query="Post"
list=()
while read filename; do
if [[ "${filename#*$query}" != "$filename" ]]; then
list+=("$filename")
fi
done <<< $(find $folder -name "*.flac")
print ${list[@]}
https://www.gnu.org/software/bash/manual/bashref.html#Here-Strings
answered Dec 29 '18 at 19:11
NickNick
11
answered Dec 29 '18 at 19:11
NickNick
11
answered Dec 29 '18 at 19:11
NickNick
11
answered Dec 29 '18 at 19:11
NickNick
11
11
This code is quite unsafe -- needs more quotes (find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.
– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put/etc/passwdin the list of results.
– Charles Duffy
Dec 29 '18 at 19:25
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0)is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).
– Charles Duffy
Dec 29 '18 at 19:26
add a comment |
This code is quite unsafe -- needs more quotes (find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.
– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put/etc/passwdin the list of results.
– Charles Duffy
Dec 29 '18 at 19:25
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0)is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).
– Charles Duffy
Dec 29 '18 at 19:26
This code is quite unsafe -- needs more quotes (
find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.– Charles Duffy
Dec 29 '18 at 19:25
This code is quite unsafe -- needs more quotes (
find "$folder"), and to use characters that can't exist in filenames (of which NUL is the only one) to separate those names.– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called
/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put /etc/passwd in the list of results.– Charles Duffy
Dec 29 '18 at 19:25
Otherwise, someone could make a file called
/home/jj/Music/Downloads/$'n'/etc/passwd$'n'/hello.flac, and your script would put /etc/passwd in the list of results.– Charles Duffy
Dec 29 '18 at 19:25
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0) is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).– Charles Duffy
Dec 29 '18 at 19:26
while IFS= read -r -d '' filename; do ...; done < <(find "$folder" -name '*.flac' -print0) is the conventional approach. Works right with real David Korn ksh93; I don't ever recommend anyone use mksh (which is inferior clone that was created while ksh93 was commercially licensed; it's now open-source, so there's no reason for mksh to exist).– Charles Duffy
Dec 29 '18 at 19:26
add a comment |
This is BashFAQ #24.
– Charles Duffy
Dec 29 '18 at 19:23