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8

0

I have two folders with similar subfolder structures, which I would like to compare. For example:

A 

├── child-1

├── child-2

├── child-3

├── child-4

├── child-5

and

B 

├── child-1-some-text

├── child-2-more-text

├── child-3-nothing

├── child-6-random-text

├── child-7-more-random-text

I would like to list all those subfolders from A which are prefix for a subfolder in B and list corresponding subfolders from B as well. The expected output is

child-1 -- child-1-some-text

child-2 -- child-2-more-text

child-3 -- child-3-nothing

A secondary requirement: If multiple matches in B, then it should give an error / warning.

My solution:

cd A

for f in `ls -d */`; 

do

    cd B;

    new_dirs=(`ls -1d $f*`);

    cd -;

    if [ ${#new_dirs[@]} -eq 0 ]

    then

        ## DO_Nothing

        continue;

    elif  [ ${#new_dirs[@]} -gt 1 ]

    then

        echo "Multiple matches to $f";

        continue;

    else

        echo "Unique Match found to $f -- ${new_dirs[0]}";

        continue;

    fi;    

done

Problem:

For those values of $f, which have no corresponding subfolders in B, the array construction is giving me an error. e.g.:

ls: cannot access 'child-4*': No such file or directory

Question

• How to get rid of these errors?


• Is there better way to achieve the goal(s) then the one in my code?

Thanks in advance!

bash directory

share|improve this question

edited yesterday

wjandrea

9,45042664

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  +1 for providing an almost working solution!
  
  – user5325
  yesterday
  

  
  
  
  

add a comment | 

8

0

I have two folders with similar subfolder structures, which I would like to compare. For example:

A 

├── child-1

├── child-2

├── child-3

├── child-4

├── child-5

and

B 

├── child-1-some-text

├── child-2-more-text

├── child-3-nothing

├── child-6-random-text

├── child-7-more-random-text

I would like to list all those subfolders from A which are prefix for a subfolder in B and list corresponding subfolders from B as well. The expected output is

child-1 -- child-1-some-text

child-2 -- child-2-more-text

child-3 -- child-3-nothing

A secondary requirement: If multiple matches in B, then it should give an error / warning.

My solution:

cd A

for f in `ls -d */`; 

do

    cd B;

    new_dirs=(`ls -1d $f*`);

    cd -;

    if [ ${#new_dirs[@]} -eq 0 ]

    then

        ## DO_Nothing

        continue;

    elif  [ ${#new_dirs[@]} -gt 1 ]

    then

        echo "Multiple matches to $f";

        continue;

    else

        echo "Unique Match found to $f -- ${new_dirs[0]}";

        continue;

    fi;    

done

Problem:

For those values of $f, which have no corresponding subfolders in B, the array construction is giving me an error. e.g.:

ls: cannot access 'child-4*': No such file or directory

Question

• How to get rid of these errors?


• Is there better way to achieve the goal(s) then the one in my code?

Thanks in advance!

bash directory

share|improve this question

edited yesterday

wjandrea

9,45042664

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  +1 for providing an almost working solution!
  
  – user5325
  yesterday
  

  
  
  
  

add a comment | 

I have two folders with similar subfolder structures, which I would like to compare. For example:

A 

├── child-1

├── child-2

├── child-3

├── child-4

├── child-5

and

B 

├── child-1-some-text

├── child-2-more-text

├── child-3-nothing

├── child-6-random-text

├── child-7-more-random-text

I would like to list all those subfolders from A which are prefix for a subfolder in B and list corresponding subfolders from B as well. The expected output is

child-1 -- child-1-some-text

child-2 -- child-2-more-text

child-3 -- child-3-nothing

A secondary requirement: If multiple matches in B, then it should give an error / warning.

My solution:

cd A

for f in `ls -d */`; 

do

    cd B;

    new_dirs=(`ls -1d $f*`);

    cd -;

    if [ ${#new_dirs[@]} -eq 0 ]

    then

        ## DO_Nothing

        continue;

    elif  [ ${#new_dirs[@]} -gt 1 ]

    then

        echo "Multiple matches to $f";

        continue;

    else

        echo "Unique Match found to $f -- ${new_dirs[0]}";

        continue;

    fi;    

done

Problem:

For those values of $f, which have no corresponding subfolders in B, the array construction is giving me an error. e.g.:

ls: cannot access 'child-4*': No such file or directory

Question

• How to get rid of these errors?


• Is there better way to achieve the goal(s) then the one in my code?

Thanks in advance!

bash directory

share|improve this question

edited yesterday

wjandrea

9,45042664

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

A 

├── child-1

├── child-2

├── child-3

├── child-4

├── child-5

B 

├── child-1-some-text

├── child-2-more-text

├── child-3-nothing

├── child-6-random-text

├── child-7-more-random-text

child-1 -- child-1-some-text

child-2 -- child-2-more-text

child-3 -- child-3-nothing

cd A

for f in `ls -d */`; 

do

    cd B;

    new_dirs=(`ls -1d $f*`);

    cd -;

    if [ ${#new_dirs[@]} -eq 0 ]

    then

        ## DO_Nothing

        continue;

    elif  [ ${#new_dirs[@]} -gt 1 ]

    then

        echo "Multiple matches to $f";

        continue;

    else

        echo "Unique Match found to $f -- ${new_dirs[0]}";

        continue;

    fi;    

done

share|improve this question

edited yesterday

wjandrea

9,45042664

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

share|improve this question

edited yesterday

wjandrea

9,45042664

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

edited yesterday

wjandrea

9,45042664

edited yesterday

wjandrea

9,45042664

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

asked yesterday

Mike V.D.C.Mike V.D.C.

3051211

2 Answers
2

active

oldest

votes

7

The better way

Don't parse ls; use globs instead. In fact you're already using globs, just wrapping them in ls, which is pointless. You just need nullglob turned on for when there are no matches.

Also avoiding cd simplifies things.

#!/bin/bash



shopt -s nullglob



dir1=A

dir2=B



for dir in "$dir1"/*/; do

    basename="$(basename -- "$dir")"

    dirs_match=( "$dir2/$basename"*/ )

    case ${#dirs_match[@]} in

    0)

        ;;

    1)

        echo "Unique match for $dir: ${dirs_match[*]}"

        ;;

    *)

        echo "Multiple matches for $dir: ${dirs_match[*]}" >&2

        ;;

    esac

done

Output:

Unique match for A/child-1/: B/child-1-some-text/

Unique match for A/child-2/: B/child-2-more-text/

Multiple matches for A/child-3/: B/child-3-nothing/ B/child-3-something/

I added B/child-3-something to test the secondary requirement. This creates the directory structure for testing:

mkdir -p A/child-{1..5} B/child-{1-some-text,2-more-text,3-nothing,3-something,6-random-text,7-more-random-text}

By the way, ShellCheck is very useful for finding problems in shell scripts.

share|improve this answer

edited yesterday

answered yesterday

wjandreawjandrea

9,45042664

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  ShellCheck.net is interesting, do you know if it uploads everything to it's own servers, or is it all done locally? Just wondering about the privacy of entered info. [Installing the shellcheck package would be the most secure]
  
  – Xen2050
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Xen2050 Just tried toggling my internet off while on the site, and it seems to upload. I would imagine it doesn't keep it, but not sure. And yes the package is good; I use an Atom plugin that uses it.
  
  – wjandrea
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for the suggestions. And also tons of thanks for pointing towards ShellCheck. I loved the part where it not only tells you your errors, but also gives suggestions! @Xen2050, about the uploading part, I just installed shellcheck using apt and then disabled network. It seems to be working without internet.
  
  – Mike V.D.C.
  21 hours ago
  

  
  
  
  

add a comment | 

2

Calling ls on a non existent folder throws the error message that you encountered. The easy way is to just ignore this by replacing line 5 in your script with this: new_dirs=(`ls -1d $f* 2> /dev/null`);.

share|improve this answer

answered yesterday

cauoncauon

1,6341021

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Have you tested this? Stderr seems to get ignored by default, when I run t=(`echo ok; echo err 1>&2`) $t (or ${t[@]}) only contains ok, err is seen in the terminal but not saved anyway. Or is there something funny about my test?
  
  – Xen2050
  3 hours ago
  
  
  

  
  
  
  

add a comment | 

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7

The better way

Don't parse ls; use globs instead. In fact you're already using globs, just wrapping them in ls, which is pointless. You just need nullglob turned on for when there are no matches.

Also avoiding cd simplifies things.

#!/bin/bash



shopt -s nullglob



dir1=A

dir2=B



for dir in "$dir1"/*/; do

    basename="$(basename -- "$dir")"

    dirs_match=( "$dir2/$basename"*/ )

    case ${#dirs_match[@]} in

    0)

        ;;

    1)

        echo "Unique match for $dir: ${dirs_match[*]}"

        ;;

    *)

        echo "Multiple matches for $dir: ${dirs_match[*]}" >&2

        ;;

    esac

done

Output:

Unique match for A/child-1/: B/child-1-some-text/

Unique match for A/child-2/: B/child-2-more-text/

Multiple matches for A/child-3/: B/child-3-nothing/ B/child-3-something/

I added B/child-3-something to test the secondary requirement. This creates the directory structure for testing:

mkdir -p A/child-{1..5} B/child-{1-some-text,2-more-text,3-nothing,3-something,6-random-text,7-more-random-text}

By the way, ShellCheck is very useful for finding problems in shell scripts.

share|improve this answer

edited yesterday

answered yesterday

wjandreawjandrea

9,45042664

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  ShellCheck.net is interesting, do you know if it uploads everything to it's own servers, or is it all done locally? Just wondering about the privacy of entered info. [Installing the shellcheck package would be the most secure]
  
  – Xen2050
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Xen2050 Just tried toggling my internet off while on the site, and it seems to upload. I would imagine it doesn't keep it, but not sure. And yes the package is good; I use an Atom plugin that uses it.
  
  – wjandrea
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for the suggestions. And also tons of thanks for pointing towards ShellCheck. I loved the part where it not only tells you your errors, but also gives suggestions! @Xen2050, about the uploading part, I just installed shellcheck using apt and then disabled network. It seems to be working without internet.
  
  – Mike V.D.C.
  21 hours ago
  

  
  
  
  

add a comment | 

7

The better way

Don't parse ls; use globs instead. In fact you're already using globs, just wrapping them in ls, which is pointless. You just need nullglob turned on for when there are no matches.

Also avoiding cd simplifies things.

#!/bin/bash



shopt -s nullglob



dir1=A

dir2=B



for dir in "$dir1"/*/; do

    basename="$(basename -- "$dir")"

    dirs_match=( "$dir2/$basename"*/ )

    case ${#dirs_match[@]} in

    0)

        ;;

    1)

        echo "Unique match for $dir: ${dirs_match[*]}"

        ;;

    *)

        echo "Multiple matches for $dir: ${dirs_match[*]}" >&2

        ;;

    esac

done

Output:

Unique match for A/child-1/: B/child-1-some-text/

Unique match for A/child-2/: B/child-2-more-text/

Multiple matches for A/child-3/: B/child-3-nothing/ B/child-3-something/

I added B/child-3-something to test the secondary requirement. This creates the directory structure for testing:

mkdir -p A/child-{1..5} B/child-{1-some-text,2-more-text,3-nothing,3-something,6-random-text,7-more-random-text}

By the way, ShellCheck is very useful for finding problems in shell scripts.

share|improve this answer

edited yesterday

answered yesterday

wjandreawjandrea

9,45042664

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  ShellCheck.net is interesting, do you know if it uploads everything to it's own servers, or is it all done locally? Just wondering about the privacy of entered info. [Installing the shellcheck package would be the most secure]
  
  – Xen2050
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Xen2050 Just tried toggling my internet off while on the site, and it seems to upload. I would imagine it doesn't keep it, but not sure. And yes the package is good; I use an Atom plugin that uses it.
  
  – wjandrea
  yesterday
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for the suggestions. And also tons of thanks for pointing towards ShellCheck. I loved the part where it not only tells you your errors, but also gives suggestions! @Xen2050, about the uploading part, I just installed shellcheck using apt and then disabled network. It seems to be working without internet.
  
  – Mike V.D.C.
  21 hours ago
  

  
  
  
  

add a comment | 

The better way

Don't parse ls; use globs instead. In fact you're already using globs, just wrapping them in ls, which is pointless. You just need nullglob turned on for when there are no matches.

Also avoiding cd simplifies things.

#!/bin/bash



shopt -s nullglob



dir1=A

dir2=B



for dir in "$dir1"/*/; do

    basename="$(basename -- "$dir")"

    dirs_match=( "$dir2/$basename"*/ )

    case ${#dirs_match[@]} in

    0)

        ;;

    1)

        echo "Unique match for $dir: ${dirs_match[*]}"

        ;;

    *)

        echo "Multiple matches for $dir: ${dirs_match[*]}" >&2

        ;;

    esac

done

Output:

Unique match for A/child-1/: B/child-1-some-text/

Unique match for A/child-2/: B/child-2-more-text/

Multiple matches for A/child-3/: B/child-3-nothing/ B/child-3-something/

I added B/child-3-something to test the secondary requirement. This creates the directory structure for testing:

mkdir -p A/child-{1..5} B/child-{1-some-text,2-more-text,3-nothing,3-something,6-random-text,7-more-random-text}

By the way, ShellCheck is very useful for finding problems in shell scripts.

share|improve this answer

edited yesterday

answered yesterday

wjandreawjandrea

9,45042664

#!/bin/bash



shopt -s nullglob



dir1=A

dir2=B



for dir in "$dir1"/*/; do

    basename="$(basename -- "$dir")"

    dirs_match=( "$dir2/$basename"*/ )

    case ${#dirs_match[@]} in

    0)

        ;;

    1)

        echo "Unique match for $dir: ${dirs_match[*]}"

        ;;

    *)

        echo "Multiple matches for $dir: ${dirs_match[*]}" >&2

        ;;

    esac

done

Unique match for A/child-1/: B/child-1-some-text/

Unique match for A/child-2/: B/child-2-more-text/

Multiple matches for A/child-3/: B/child-3-nothing/ B/child-3-something/

mkdir -p A/child-{1..5} B/child-{1-some-text,2-more-text,3-nothing,3-something,6-random-text,7-more-random-text}

share|improve this answer

edited yesterday

answered yesterday

wjandreawjandrea

9,45042664

answered yesterday

wjandreawjandrea

9,45042664

answered yesterday

wjandreawjandrea

9,45042664

2

Calling ls on a non existent folder throws the error message that you encountered. The easy way is to just ignore this by replacing line 5 in your script with this: new_dirs=(`ls -1d $f* 2> /dev/null`);.

share|improve this answer

answered yesterday

cauoncauon

1,6341021

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Have you tested this? Stderr seems to get ignored by default, when I run t=(`echo ok; echo err 1>&2`) $t (or ${t[@]}) only contains ok, err is seen in the terminal but not saved anyway. Or is there something funny about my test?
  
  – Xen2050
  3 hours ago
  
  
  

  
  
  
  

add a comment | 

2

Calling ls on a non existent folder throws the error message that you encountered. The easy way is to just ignore this by replacing line 5 in your script with this: new_dirs=(`ls -1d $f* 2> /dev/null`);.

share|improve this answer

answered yesterday

cauoncauon

1,6341021

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Have you tested this? Stderr seems to get ignored by default, when I run t=(`echo ok; echo err 1>&2`) $t (or ${t[@]}) only contains ok, err is seen in the terminal but not saved anyway. Or is there something funny about my test?
  
  – Xen2050
  3 hours ago
  
  
  

  
  
  
  

add a comment | 

Calling ls on a non existent folder throws the error message that you encountered. The easy way is to just ignore this by replacing line 5 in your script with this: new_dirs=(`ls -1d $f* 2> /dev/null`);.

share|improve this answer

answered yesterday

cauoncauon

1,6341021

share|improve this answer

answered yesterday

cauoncauon

1,6341021

answered yesterday

cauoncauon

1,6341021

answered yesterday

cauoncauon

1,6341021