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3

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '') 2> /dev/null

where foo is a directory

It's reading the full pathname of foo and creating it as a file replacing all '/' with '' and putting a directory_ in front so the directory
/home/test/foo would create a file directory_hometestfoo

It does exactly what I want except a warning keeps printing tr: warning: an unescaped backslash at end of string is not portable

a. I don't know what that means
b. I would like it to not show

I tried to redirect stderr to /dev/null but it doesn't work. How do I suppress it?

bash command-substitution stderr

share|improve this question

edited Apr 5 at 3:00

muru

37.2k589164

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Please edit and clarify how you use this. Are you calling it as a function? Where is $1 defined? You should also be aware that while are allowed in file names, it is a Very Bad Idea® to include them and it will lead to all sorts of trouble later on.
  
  – terdon♦
  Aug 6 '14 at 14:37
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It's in a script. to run it I "sh script nameOfDirectory"
  
  – lonewarrior556
  Aug 6 '14 at 14:38
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Please edit your question to clarify accordingly. I also strongly suggest you consider using any other character but , backslashes are special as you're finding out.
  
  – terdon♦
  Aug 6 '14 at 14:39
  
  

  
  
  
  

add a comment | 

3

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '') 2> /dev/null

where foo is a directory

It's reading the full pathname of foo and creating it as a file replacing all '/' with '' and putting a directory_ in front so the directory
/home/test/foo would create a file directory_hometestfoo

It does exactly what I want except a warning keeps printing tr: warning: an unescaped backslash at end of string is not portable

a. I don't know what that means
b. I would like it to not show

I tried to redirect stderr to /dev/null but it doesn't work. How do I suppress it?

bash command-substitution stderr

share|improve this question

edited Apr 5 at 3:00

muru

37.2k589164

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Please edit and clarify how you use this. Are you calling it as a function? Where is $1 defined? You should also be aware that while are allowed in file names, it is a Very Bad Idea® to include them and it will lead to all sorts of trouble later on.
  
  – terdon♦
  Aug 6 '14 at 14:37
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  It's in a script. to run it I "sh script nameOfDirectory"
  
  – lonewarrior556
  Aug 6 '14 at 14:38
  
  

  
  
  
  


• 
  
  
  

  
  3
  

  
  
  
  
  
  

  
  
  Please edit your question to clarify accordingly. I also strongly suggest you consider using any other character but , backslashes are special as you're finding out.
  
  – terdon♦
  Aug 6 '14 at 14:39
  
  

  
  
  
  

add a comment | 

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '') 2> /dev/null

where foo is a directory

It's reading the full pathname of foo and creating it as a file replacing all '/' with '' and putting a directory_ in front so the directory
/home/test/foo would create a file directory_hometestfoo

It does exactly what I want except a warning keeps printing tr: warning: an unescaped backslash at end of string is not portable

a. I don't know what that means
b. I would like it to not show

I tried to redirect stderr to /dev/null but it doesn't work. How do I suppress it?

bash command-substitution stderr

share|improve this question

edited Apr 5 at 3:00

muru

37.2k589164

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '') 2> /dev/null

share|improve this question

edited Apr 5 at 3:00

muru

37.2k589164

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

share|improve this question

edited Apr 5 at 3:00

muru

37.2k589164

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

edited Apr 5 at 3:00

muru

37.2k589164

edited Apr 5 at 3:00

muru

37.2k589164

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

asked Aug 6 '14 at 14:32

lonewarrior556lonewarrior556

6683813

3 Answers
3

active

oldest

votes

3

Some expansions happen before redirection so you have to place it directly against your tr command:

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '' 2> /dev/null)

share|improve this answer

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

add a comment | 

4

The error message means that you have an unescaped backslash. In the *nix world, special characters are 'escaped' by adding a backslash before them. That means that they're interpreted as simple characters and not special ones. For example:

$ printf 'foonbar'
foo
bar

The n is a special character that means newline. But if we escape the slash we get:

$ printf 'foo\nbar'
foonbar

So, you can get rid of it either by escaping the backslash:

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '\')

Or by redirecting the error output of tr (not of touch which is what you were doing):

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '' 2> /dev/null)

However, I cannot stress enough that it is a Very Bad Idea® to create file names with backslashes. Really. They will be hell to parse and deal with later on. Why not use another character?

share|improve this answer

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Maybe the OP from windows environment?
  
  – cuonglm
  Aug 6 '14 at 15:16
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Gnouc yes, which means it's an even worse idea to use ``.
  
  – terdon♦
  Aug 6 '14 at 15:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Git Bash in Windows 10 complains about [...] | tr '\' '/' although the backslash is properly escaped. Go figure.
  
  – Rolf
  Jan 23 at 16:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Rolf Windows uses `` as the path delimiter, so that might cause issues there.
  
  – terdon♦
  Jan 23 at 17:19
  

  
  
  
  

add a comment | 

2

Use single quotes with double back slash, and you will not get any error.

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '\')

share|improve this answer

edited Aug 28 '17 at 10:07

zagrimsan

694519

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Fun thing is, if url=D:ProgramsGitmingw64/share/doc/git-doc/git-log.html then ``url1=echo $url | tr '\ '/'``` shows the warning, while url1=$(echo $url | tr '\' '/')` does not.
  
  – ThomasH
  Dec 19 '18 at 9:00
  
  

  
  
  
  

add a comment | 

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3

Some expansions happen before redirection so you have to place it directly against your tr command:

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '' 2> /dev/null)

share|improve this answer

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

add a comment | 

3

Some expansions happen before redirection so you have to place it directly against your tr command:

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '' 2> /dev/null)

share|improve this answer

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

add a comment | 

Some expansions happen before redirection so you have to place it directly against your tr command:

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '' 2> /dev/null)

share|improve this answer

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '' 2> /dev/null)

share|improve this answer

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

answered Aug 6 '14 at 14:43

konsoleboxkonsolebox

1,297109

4

The error message means that you have an unescaped backslash. In the *nix world, special characters are 'escaped' by adding a backslash before them. That means that they're interpreted as simple characters and not special ones. For example:

$ printf 'foonbar'
foo
bar

The n is a special character that means newline. But if we escape the slash we get:

$ printf 'foo\nbar'
foonbar

So, you can get rid of it either by escaping the backslash:

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '\')

Or by redirecting the error output of tr (not of touch which is what you were doing):

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '' 2> /dev/null)

However, I cannot stress enough that it is a Very Bad Idea® to create file names with backslashes. Really. They will be hell to parse and deal with later on. Why not use another character?

share|improve this answer

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Maybe the OP from windows environment?
  
  – cuonglm
  Aug 6 '14 at 15:16
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Gnouc yes, which means it's an even worse idea to use ``.
  
  – terdon♦
  Aug 6 '14 at 15:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Git Bash in Windows 10 complains about [...] | tr '\' '/' although the backslash is properly escaped. Go figure.
  
  – Rolf
  Jan 23 at 16:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Rolf Windows uses `` as the path delimiter, so that might cause issues there.
  
  – terdon♦
  Jan 23 at 17:19
  

  
  
  
  

add a comment | 

4

The error message means that you have an unescaped backslash. In the *nix world, special characters are 'escaped' by adding a backslash before them. That means that they're interpreted as simple characters and not special ones. For example:

$ printf 'foonbar'
foo
bar

The n is a special character that means newline. But if we escape the slash we get:

$ printf 'foo\nbar'
foonbar

So, you can get rid of it either by escaping the backslash:

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '\')

Or by redirecting the error output of tr (not of touch which is what you were doing):

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '' 2> /dev/null)

However, I cannot stress enough that it is a Very Bad Idea® to create file names with backslashes. Really. They will be hell to parse and deal with later on. Why not use another character?

share|improve this answer

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Maybe the OP from windows environment?
  
  – cuonglm
  Aug 6 '14 at 15:16
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Gnouc yes, which means it's an even worse idea to use ``.
  
  – terdon♦
  Aug 6 '14 at 15:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Git Bash in Windows 10 complains about [...] | tr '\' '/' although the backslash is properly escaped. Go figure.
  
  – Rolf
  Jan 23 at 16:58
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Rolf Windows uses `` as the path delimiter, so that might cause issues there.
  
  – terdon♦
  Jan 23 at 17:19
  

  
  
  
  

add a comment | 

The error message means that you have an unescaped backslash. In the *nix world, special characters are 'escaped' by adding a backslash before them. That means that they're interpreted as simple characters and not special ones. For example:

$ printf 'foonbar'
foo
bar

The n is a special character that means newline. But if we escape the slash we get:

$ printf 'foo\nbar'
foonbar

So, you can get rid of it either by escaping the backslash:

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '\')

Or by redirecting the error output of tr (not of touch which is what you were doing):

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '' 2> /dev/null)

However, I cannot stress enough that it is a Very Bad Idea® to create file names with backslashes. Really. They will be hell to parse and deal with later on. Why not use another character?

share|improve this answer

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

$ printf 'foonbar'
foo
bar

$ printf 'foo\nbar'
foonbar

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '\')

touch ~/deleted/"$(echo "directory_$(readlink -f -- "$1")"|tr '/' '' 2> /dev/null)

share|improve this answer

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

edited Aug 6 '14 at 15:21

Stéphane Chazelas

313k57593949

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

answered Aug 6 '14 at 14:43

terdon♦terdon

134k33268449

2

Use single quotes with double back slash, and you will not get any error.

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '\')

share|improve this answer

edited Aug 28 '17 at 10:07

zagrimsan

694519

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Fun thing is, if url=D:ProgramsGitmingw64/share/doc/git-doc/git-log.html then ``url1=echo $url | tr '\ '/'``` shows the warning, while url1=$(echo $url | tr '\' '/')` does not.
  
  – ThomasH
  Dec 19 '18 at 9:00
  
  

  
  
  
  

add a comment | 

2

Use single quotes with double back slash, and you will not get any error.

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '\')

share|improve this answer

edited Aug 28 '17 at 10:07

zagrimsan

694519

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Fun thing is, if url=D:ProgramsGitmingw64/share/doc/git-doc/git-log.html then ``url1=echo $url | tr '\ '/'``` shows the warning, while url1=$(echo $url | tr '\' '/')` does not.
  
  – ThomasH
  Dec 19 '18 at 9:00
  
  

  
  
  
  

add a comment | 

Use single quotes with double back slash, and you will not get any error.

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '\')

share|improve this answer

edited Aug 28 '17 at 10:07

zagrimsan

694519

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211

touch ~/deleted/$(echo "directory_"$(readlink -f foo)|tr '/' '\')

share|improve this answer

edited Aug 28 '17 at 10:07

zagrimsan

694519

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211

edited Aug 28 '17 at 10:07

zagrimsan

694519

edited Aug 28 '17 at 10:07

zagrimsan

694519

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211

answered Aug 28 '17 at 9:12

Tayyab KhanTayyab Khan

211