Search for special characters using grep

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up vote
6
down vote

favorite

1

I want to search for the lines that contains any of the following characters:

: / / ? # [ ] @ ! $ & ' ( ) * + , ; = %

I am familiar with grep. But with this set of characters, it is a bit tricky and I would rather ask for help.

grep string search file-search

share|improve this question

asked Aug 17 at 14:53

user9371654

1226

add a comment | 

up vote
6
down vote

favorite

1

I want to search for the lines that contains any of the following characters:

: / / ? # [ ] @ ! $ & ' ( ) * + , ; = %

I am familiar with grep. But with this set of characters, it is a bit tricky and I would rather ask for help.

grep string search file-search

share|improve this question

asked Aug 17 at 14:53

user9371654

1226

add a comment | 

up vote
6
down vote

favorite

1

up vote
6
down vote

favorite

1

1

I want to search for the lines that contains any of the following characters:

: / / ? # [ ] @ ! $ & ' ( ) * + , ; = %

I am familiar with grep. But with this set of characters, it is a bit tricky and I would rather ask for help.

grep string search file-search

share|improve this question

asked Aug 17 at 14:53

user9371654

1226

I want to search for the lines that contains any of the following characters:

: / / ? # [ ] @ ! $ & ' ( ) * + , ; = %

I am familiar with grep. But with this set of characters, it is a bit tricky and I would rather ask for help.

grep string search file-search

share|improve this question

asked Aug 17 at 14:53

user9371654

1226

share|improve this question

share|improve this question

asked Aug 17 at 14:53

user9371654

1226

asked Aug 17 at 14:53

user9371654

1226

asked Aug 17 at 14:53

user9371654

1226

1226

add a comment | 

add a comment | 

3 Answers
3

active

oldest

votes

up vote
7
down vote



accepted

grep ":/?#@!$&'()*+,;=%"

Within a bracketed expression, [...], very few character are "special" (only a very small subset, like ], - and ^, and the three combinations [=, [: and [.). When including ] in [...], the ] must come first (possibly after a ^). I opted to put the ] first and the [ last for symmetry.

The only other thing to remember is that a single quoted string can not include a single quote, so we use double quotes around the expression. Since we use a double quoted string, the shell will poke around in it for things to expand. For this reason, we escape the $ as $ which will make the shell give a literal $ to grep, and we escape ! as ! too as it's a history expansion in bash (only in interactive bash shells though).

Would you want to include a backslash in the set, you would have to escape it as \ so that the shell gives a single backslash to grep. Also, if you want to include a backtick `, it too must be escaped as ` as it starts a command substitution otherwise.

The command above would extract any line that contained at least one of the characters in the bracketed expression.

---

Using a single quoted string instead of a double quoted string, which gets around most of the annoyances with what characters the shell interprets:

grep ':/?#@!$&'"'"'()*+,;=%'

Here, the only thing to remember, apart from the placing of the ], is that a single quoted string can not include a single quote, so instead we use a concatenation of three strings:

1. ':/?#@!$&'


2. "'"


3. '()*+,;=%'

share|improve this answer

edited Aug 17 at 17:06

answered Aug 17 at 15:04

Kusalananda

105k14206325

• 
  
  
  

  
  

  
  
  
  
  
  

  
  @ilkkachu I didn't spot the $ in there! Thanks!
  – Kusalananda
  Aug 17 at 15:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  When I try to execute the command, I get this error bash: !: event not found.
  – user9371654
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
  – Kusalananda
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  "[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
  – Stéphane Chazelas
  Aug 17 at 15:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
  – Stéphane Chazelas
  Aug 17 at 15:56
  

  
  
  
  

 | 
show 2 more comments

up vote
5
down vote

You can use [:punct:] character class if you don't mind that it also matches other punctuation and special characters:

grep '[[:punct:]]' file

share|improve this answer

edited Aug 17 at 15:29

ilkkachu

50.3k677138

answered Aug 17 at 15:01

Alexander

65012

• 
  
  
  

  
  

  
  
  
  
  
  

  
  The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
  – Kusalananda
  Aug 17 at 15:17
  

  
  
  
  

add a comment | 

up vote
4
down vote

You can use full regex to find special characters inside of square brackets if your looking for one character that is a special character. A great resource practicing, learning and checking your Regular Expression is regex101.com.

This uses Perl regular expressions, which can be used with GNU grep with the -P option:

grep -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"
 ^^^

Note that you need two backslashes in front of the dollar sign, as it has a special meaning in the shell, and the first backslash will escape it for the shell. ^{(With just one backslash in front, the shell would remove the backslash, grep would see an unescaped dollar sign meaning end of line, and match any input line.)}

If your terminal supports colors, throw colors on as well,

grep --color=auto -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"

Here is the explanation of my regex from regex101.com

/(:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])/gm
1st Capturing Group (:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])
 : matches the character : literally (case sensitive)
 / matches the character / literally (case sensitive)
 ? matches the character ? literally (case sensitive)
 # matches the character # literally (case sensitive)
 @ matches the character @ literally (case sensitive)
 ! matches the character ! literally (case sensitive)
 $ matches the character $ literally (case sensitive)
 & matches the character & literally (case sensitive)
 ' matches the character ' literally (case sensitive)
 ( matches the character ( literally (case sensitive)
 ) matches the character ) literally (case sensitive)
 * matches the character * literally (case sensitive)
 + matches the character + literally (case sensitive)
 , matches the character , literally (case sensitive)
 ; matches the character ; literally (case sensitive)
 = matches the character = literally (case sensitive)
 % matches the character % literally (case sensitive)
 [ matches the character [ literally (case sensitive)
 ] matches the character ] literally (case sensitive)

share|improve this answer

edited Aug 18 at 8:38

ilkkachu

50.3k677138

answered Aug 17 at 15:31

thebtm

655411

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
  – Stéphane Chazelas
  Aug 17 at 15:42
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
  – ilkkachu
  Aug 17 at 15:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Corrected to -P, sorry about that, i get the -E and -P mixed up
  – thebtm
  Aug 17 at 15:47
  

  
  
  
  

add a comment | 

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3 Answers
3

active

oldest

votes

3 Answers
3

active

oldest

votes

active

oldest

votes

active

oldest

votes

up vote
7
down vote



accepted

grep ":/?#@!$&'()*+,;=%"

Within a bracketed expression, [...], very few character are "special" (only a very small subset, like ], - and ^, and the three combinations [=, [: and [.). When including ] in [...], the ] must come first (possibly after a ^). I opted to put the ] first and the [ last for symmetry.

The only other thing to remember is that a single quoted string can not include a single quote, so we use double quotes around the expression. Since we use a double quoted string, the shell will poke around in it for things to expand. For this reason, we escape the $ as $ which will make the shell give a literal $ to grep, and we escape ! as ! too as it's a history expansion in bash (only in interactive bash shells though).

Would you want to include a backslash in the set, you would have to escape it as \ so that the shell gives a single backslash to grep. Also, if you want to include a backtick `, it too must be escaped as ` as it starts a command substitution otherwise.

The command above would extract any line that contained at least one of the characters in the bracketed expression.

---

Using a single quoted string instead of a double quoted string, which gets around most of the annoyances with what characters the shell interprets:

grep ':/?#@!$&'"'"'()*+,;=%'

Here, the only thing to remember, apart from the placing of the ], is that a single quoted string can not include a single quote, so instead we use a concatenation of three strings:

1. ':/?#@!$&'


2. "'"


3. '()*+,;=%'

share|improve this answer

edited Aug 17 at 17:06

answered Aug 17 at 15:04

Kusalananda

105k14206325

• 
  
  
  

  
  

  
  
  
  
  
  

  
  @ilkkachu I didn't spot the $ in there! Thanks!
  – Kusalananda
  Aug 17 at 15:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  When I try to execute the command, I get this error bash: !: event not found.
  – user9371654
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
  – Kusalananda
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  "[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
  – Stéphane Chazelas
  Aug 17 at 15:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
  – Stéphane Chazelas
  Aug 17 at 15:56
  

  
  
  
  

 | 
show 2 more comments

up vote
7
down vote



accepted

grep ":/?#@!$&'()*+,;=%"

Within a bracketed expression, [...], very few character are "special" (only a very small subset, like ], - and ^, and the three combinations [=, [: and [.). When including ] in [...], the ] must come first (possibly after a ^). I opted to put the ] first and the [ last for symmetry.

The only other thing to remember is that a single quoted string can not include a single quote, so we use double quotes around the expression. Since we use a double quoted string, the shell will poke around in it for things to expand. For this reason, we escape the $ as $ which will make the shell give a literal $ to grep, and we escape ! as ! too as it's a history expansion in bash (only in interactive bash shells though).

Would you want to include a backslash in the set, you would have to escape it as \ so that the shell gives a single backslash to grep. Also, if you want to include a backtick `, it too must be escaped as ` as it starts a command substitution otherwise.

The command above would extract any line that contained at least one of the characters in the bracketed expression.

---

Using a single quoted string instead of a double quoted string, which gets around most of the annoyances with what characters the shell interprets:

grep ':/?#@!$&'"'"'()*+,;=%'

Here, the only thing to remember, apart from the placing of the ], is that a single quoted string can not include a single quote, so instead we use a concatenation of three strings:

1. ':/?#@!$&'


2. "'"


3. '()*+,;=%'

share|improve this answer

edited Aug 17 at 17:06

answered Aug 17 at 15:04

Kusalananda

105k14206325

• 
  
  
  

  
  

  
  
  
  
  
  

  
  @ilkkachu I didn't spot the $ in there! Thanks!
  – Kusalananda
  Aug 17 at 15:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  When I try to execute the command, I get this error bash: !: event not found.
  – user9371654
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
  – Kusalananda
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  "[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
  – Stéphane Chazelas
  Aug 17 at 15:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
  – Stéphane Chazelas
  Aug 17 at 15:56
  

  
  
  
  

 | 
show 2 more comments

up vote
7
down vote



accepted

up vote
7
down vote



accepted

grep ":/?#@!$&'()*+,;=%"

Within a bracketed expression, [...], very few character are "special" (only a very small subset, like ], - and ^, and the three combinations [=, [: and [.). When including ] in [...], the ] must come first (possibly after a ^). I opted to put the ] first and the [ last for symmetry.

The only other thing to remember is that a single quoted string can not include a single quote, so we use double quotes around the expression. Since we use a double quoted string, the shell will poke around in it for things to expand. For this reason, we escape the $ as $ which will make the shell give a literal $ to grep, and we escape ! as ! too as it's a history expansion in bash (only in interactive bash shells though).

Would you want to include a backslash in the set, you would have to escape it as \ so that the shell gives a single backslash to grep. Also, if you want to include a backtick `, it too must be escaped as ` as it starts a command substitution otherwise.

The command above would extract any line that contained at least one of the characters in the bracketed expression.

---

Using a single quoted string instead of a double quoted string, which gets around most of the annoyances with what characters the shell interprets:

grep ':/?#@!$&'"'"'()*+,;=%'

Here, the only thing to remember, apart from the placing of the ], is that a single quoted string can not include a single quote, so instead we use a concatenation of three strings:

1. ':/?#@!$&'


2. "'"


3. '()*+,;=%'

share|improve this answer

edited Aug 17 at 17:06

answered Aug 17 at 15:04

Kusalananda

105k14206325

grep ":/?#@!$&'()*+,;=%"

Within a bracketed expression, [...], very few character are "special" (only a very small subset, like ], - and ^, and the three combinations [=, [: and [.). When including ] in [...], the ] must come first (possibly after a ^). I opted to put the ] first and the [ last for symmetry.

The only other thing to remember is that a single quoted string can not include a single quote, so we use double quotes around the expression. Since we use a double quoted string, the shell will poke around in it for things to expand. For this reason, we escape the $ as $ which will make the shell give a literal $ to grep, and we escape ! as ! too as it's a history expansion in bash (only in interactive bash shells though).

Would you want to include a backslash in the set, you would have to escape it as \ so that the shell gives a single backslash to grep. Also, if you want to include a backtick `, it too must be escaped as ` as it starts a command substitution otherwise.

The command above would extract any line that contained at least one of the characters in the bracketed expression.

---

Using a single quoted string instead of a double quoted string, which gets around most of the annoyances with what characters the shell interprets:

grep ':/?#@!$&'"'"'()*+,;=%'

Here, the only thing to remember, apart from the placing of the ], is that a single quoted string can not include a single quote, so instead we use a concatenation of three strings:

1. ':/?#@!$&'


2. "'"


3. '()*+,;=%'

share|improve this answer

edited Aug 17 at 17:06

answered Aug 17 at 15:04

Kusalananda

105k14206325

share|improve this answer

share|improve this answer

edited Aug 17 at 17:06

edited Aug 17 at 17:06

edited Aug 17 at 17:06

answered Aug 17 at 15:04

Kusalananda

105k14206325

answered Aug 17 at 15:04

Kusalananda

105k14206325

answered Aug 17 at 15:04

Kusalananda

105k14206325

105k14206325

• 
  
  
  

  
  

  
  
  
  
  
  

  
  @ilkkachu I didn't spot the $ in there! Thanks!
  – Kusalananda
  Aug 17 at 15:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  When I try to execute the command, I get this error bash: !: event not found.
  – user9371654
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
  – Kusalananda
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  "[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
  – Stéphane Chazelas
  Aug 17 at 15:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
  – Stéphane Chazelas
  Aug 17 at 15:56
  

  
  
  
  

 | 
show 2 more comments

• 
  
  
  

  
  

  
  
  
  
  
  

  
  @ilkkachu I didn't spot the $ in there! Thanks!
  – Kusalananda
  Aug 17 at 15:09
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  When I try to execute the command, I get this error bash: !: event not found.
  – user9371654
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  @user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
  – Kusalananda
  Aug 17 at 15:14
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  "[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
  – Stéphane Chazelas
  Aug 17 at 15:36
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
  – Stéphane Chazelas
  Aug 17 at 15:56
  

  
  
  
  

@ilkkachu I didn't spot the $ in there! Thanks!
– Kusalananda
Aug 17 at 15:09

@ilkkachu I didn't spot the $ in there! Thanks!
– Kusalananda
Aug 17 at 15:09

When I try to execute the command, I get this error bash: !: event not found.
– user9371654
Aug 17 at 15:14

When I try to execute the command, I get this error bash: !: event not found.
– user9371654
Aug 17 at 15:14

@user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
– Kusalananda
Aug 17 at 15:14

@user9371654 Darn bash! :-) Escape the ! too... Not being a bash user I forgot about that. I will update...
– Kusalananda
Aug 17 at 15:14

1

1

"[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
– Stéphane Chazelas
Aug 17 at 15:36

"[!]" expands to [!] even when history expansion is enabled, so would match on backslash. You'd need single quotes or using ! outside of quotes.
– Stéphane Chazelas
Aug 17 at 15:36

1

1

Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
– Stéphane Chazelas
Aug 17 at 15:56

Note that it's not only bash, zsh also has that annoying feature inherited from csh. in csh, ! special inside '...' as well, and also when non-interactive. However in csh (contrary to bash or zsh), using "!" would work here (the backslash is removed).
– Stéphane Chazelas
Aug 17 at 15:56

 | 
show 2 more comments

up vote
5
down vote

You can use [:punct:] character class if you don't mind that it also matches other punctuation and special characters:

grep '[[:punct:]]' file

share|improve this answer

edited Aug 17 at 15:29

ilkkachu

50.3k677138

answered Aug 17 at 15:01

Alexander

65012

• 
  
  
  

  
  

  
  
  
  
  
  

  
  The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
  – Kusalananda
  Aug 17 at 15:17
  

  
  
  
  

add a comment | 

up vote
5
down vote

You can use [:punct:] character class if you don't mind that it also matches other punctuation and special characters:

grep '[[:punct:]]' file

share|improve this answer

edited Aug 17 at 15:29

ilkkachu

50.3k677138

answered Aug 17 at 15:01

Alexander

65012

• 
  
  
  

  
  

  
  
  
  
  
  

  
  The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
  – Kusalananda
  Aug 17 at 15:17
  

  
  
  
  

add a comment | 

up vote
5
down vote

up vote
5
down vote

You can use [:punct:] character class if you don't mind that it also matches other punctuation and special characters:

grep '[[:punct:]]' file

share|improve this answer

edited Aug 17 at 15:29

ilkkachu

50.3k677138

answered Aug 17 at 15:01

Alexander

65012

You can use [:punct:] character class if you don't mind that it also matches other punctuation and special characters:

grep '[[:punct:]]' file

share|improve this answer

edited Aug 17 at 15:29

ilkkachu

50.3k677138

answered Aug 17 at 15:01

Alexander

65012

share|improve this answer

share|improve this answer

edited Aug 17 at 15:29

ilkkachu

50.3k677138

edited Aug 17 at 15:29

ilkkachu

50.3k677138

edited Aug 17 at 15:29

ilkkachu

50.3k677138

50.3k677138

answered Aug 17 at 15:01

Alexander

65012

answered Aug 17 at 15:01

Alexander

65012

answered Aug 17 at 15:01

Alexander

65012

65012

• 
  
  
  

  
  

  
  
  
  
  
  

  
  The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
  – Kusalananda
  Aug 17 at 15:17
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  

  
  
  
  
  
  

  
  The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
  – Kusalananda
  Aug 17 at 15:17
  

  
  
  
  

The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
– Kusalananda
Aug 17 at 15:17

The punct character class (not macro) matches !"#$%&'()*+,-./:;<=>?@[]^_~` in the C locale, which is a slightly larges set of characters than what the user has, but it may be good enough.
– Kusalananda
Aug 17 at 15:17

add a comment | 

up vote
4
down vote

You can use full regex to find special characters inside of square brackets if your looking for one character that is a special character. A great resource practicing, learning and checking your Regular Expression is regex101.com.

This uses Perl regular expressions, which can be used with GNU grep with the -P option:

grep -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"
 ^^^

Note that you need two backslashes in front of the dollar sign, as it has a special meaning in the shell, and the first backslash will escape it for the shell. ^{(With just one backslash in front, the shell would remove the backslash, grep would see an unescaped dollar sign meaning end of line, and match any input line.)}

If your terminal supports colors, throw colors on as well,

grep --color=auto -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"

Here is the explanation of my regex from regex101.com

/(:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])/gm
1st Capturing Group (:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])
 : matches the character : literally (case sensitive)
 / matches the character / literally (case sensitive)
 ? matches the character ? literally (case sensitive)
 # matches the character # literally (case sensitive)
 @ matches the character @ literally (case sensitive)
 ! matches the character ! literally (case sensitive)
 $ matches the character $ literally (case sensitive)
 & matches the character & literally (case sensitive)
 ' matches the character ' literally (case sensitive)
 ( matches the character ( literally (case sensitive)
 ) matches the character ) literally (case sensitive)
 * matches the character * literally (case sensitive)
 + matches the character + literally (case sensitive)
 , matches the character , literally (case sensitive)
 ; matches the character ; literally (case sensitive)
 = matches the character = literally (case sensitive)
 % matches the character % literally (case sensitive)
 [ matches the character [ literally (case sensitive)
 ] matches the character ] literally (case sensitive)

share|improve this answer

edited Aug 18 at 8:38

ilkkachu

50.3k677138

answered Aug 17 at 15:31

thebtm

655411

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
  – Stéphane Chazelas
  Aug 17 at 15:42
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
  – ilkkachu
  Aug 17 at 15:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Corrected to -P, sorry about that, i get the -E and -P mixed up
  – thebtm
  Aug 17 at 15:47
  

  
  
  
  

add a comment | 

up vote
4
down vote

You can use full regex to find special characters inside of square brackets if your looking for one character that is a special character. A great resource practicing, learning and checking your Regular Expression is regex101.com.

This uses Perl regular expressions, which can be used with GNU grep with the -P option:

grep -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"
 ^^^

Note that you need two backslashes in front of the dollar sign, as it has a special meaning in the shell, and the first backslash will escape it for the shell. ^{(With just one backslash in front, the shell would remove the backslash, grep would see an unescaped dollar sign meaning end of line, and match any input line.)}

If your terminal supports colors, throw colors on as well,

grep --color=auto -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"

Here is the explanation of my regex from regex101.com

/(:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])/gm
1st Capturing Group (:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])
 : matches the character : literally (case sensitive)
 / matches the character / literally (case sensitive)
 ? matches the character ? literally (case sensitive)
 # matches the character # literally (case sensitive)
 @ matches the character @ literally (case sensitive)
 ! matches the character ! literally (case sensitive)
 $ matches the character $ literally (case sensitive)
 & matches the character & literally (case sensitive)
 ' matches the character ' literally (case sensitive)
 ( matches the character ( literally (case sensitive)
 ) matches the character ) literally (case sensitive)
 * matches the character * literally (case sensitive)
 + matches the character + literally (case sensitive)
 , matches the character , literally (case sensitive)
 ; matches the character ; literally (case sensitive)
 = matches the character = literally (case sensitive)
 % matches the character % literally (case sensitive)
 [ matches the character [ literally (case sensitive)
 ] matches the character ] literally (case sensitive)

share|improve this answer

edited Aug 18 at 8:38

ilkkachu

50.3k677138

answered Aug 17 at 15:31

thebtm

655411

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
  – Stéphane Chazelas
  Aug 17 at 15:42
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
  – ilkkachu
  Aug 17 at 15:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Corrected to -P, sorry about that, i get the -E and -P mixed up
  – thebtm
  Aug 17 at 15:47
  

  
  
  
  

add a comment | 

up vote
4
down vote

up vote
4
down vote

You can use full regex to find special characters inside of square brackets if your looking for one character that is a special character. A great resource practicing, learning and checking your Regular Expression is regex101.com.

This uses Perl regular expressions, which can be used with GNU grep with the -P option:

grep -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"
 ^^^

Note that you need two backslashes in front of the dollar sign, as it has a special meaning in the shell, and the first backslash will escape it for the shell. ^{(With just one backslash in front, the shell would remove the backslash, grep would see an unescaped dollar sign meaning end of line, and match any input line.)}

If your terminal supports colors, throw colors on as well,

grep --color=auto -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"

Here is the explanation of my regex from regex101.com

/(:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])/gm
1st Capturing Group (:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])
 : matches the character : literally (case sensitive)
 / matches the character / literally (case sensitive)
 ? matches the character ? literally (case sensitive)
 # matches the character # literally (case sensitive)
 @ matches the character @ literally (case sensitive)
 ! matches the character ! literally (case sensitive)
 $ matches the character $ literally (case sensitive)
 & matches the character & literally (case sensitive)
 ' matches the character ' literally (case sensitive)
 ( matches the character ( literally (case sensitive)
 ) matches the character ) literally (case sensitive)
 * matches the character * literally (case sensitive)
 + matches the character + literally (case sensitive)
 , matches the character , literally (case sensitive)
 ; matches the character ; literally (case sensitive)
 = matches the character = literally (case sensitive)
 % matches the character % literally (case sensitive)
 [ matches the character [ literally (case sensitive)
 ] matches the character ] literally (case sensitive)

share|improve this answer

edited Aug 18 at 8:38

ilkkachu

50.3k677138

answered Aug 17 at 15:31

thebtm

655411

You can use full regex to find special characters inside of square brackets if your looking for one character that is a special character. A great resource practicing, learning and checking your Regular Expression is regex101.com.

This uses Perl regular expressions, which can be used with GNU grep with the -P option:

grep -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"
 ^^^

Note that you need two backslashes in front of the dollar sign, as it has a special meaning in the shell, and the first backslash will escape it for the shell. ^{(With just one backslash in front, the shell would remove the backslash, grep would see an unescaped dollar sign meaning end of line, and match any input line.)}

If your terminal supports colors, throw colors on as well,

grep --color=auto -P "(:|/|?|#|@|!|\$|&|'|(|)|*|+|,|;|=|%|[|])"

Here is the explanation of my regex from regex101.com

/(:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])/gm
1st Capturing Group (:|/|?|#|@|!|$|&|'|(|)|*|+|,|;|=|%|[|])
 : matches the character : literally (case sensitive)
 / matches the character / literally (case sensitive)
 ? matches the character ? literally (case sensitive)
 # matches the character # literally (case sensitive)
 @ matches the character @ literally (case sensitive)
 ! matches the character ! literally (case sensitive)
 $ matches the character $ literally (case sensitive)
 & matches the character & literally (case sensitive)
 ' matches the character ' literally (case sensitive)
 ( matches the character ( literally (case sensitive)
 ) matches the character ) literally (case sensitive)
 * matches the character * literally (case sensitive)
 + matches the character + literally (case sensitive)
 , matches the character , literally (case sensitive)
 ; matches the character ; literally (case sensitive)
 = matches the character = literally (case sensitive)
 % matches the character % literally (case sensitive)
 [ matches the character [ literally (case sensitive)
 ] matches the character ] literally (case sensitive)

share|improve this answer

edited Aug 18 at 8:38

ilkkachu

50.3k677138

answered Aug 17 at 15:31

thebtm

655411

share|improve this answer

share|improve this answer

edited Aug 18 at 8:38

ilkkachu

50.3k677138

edited Aug 18 at 8:38

ilkkachu

50.3k677138

edited Aug 18 at 8:38

ilkkachu

50.3k677138

50.3k677138

answered Aug 17 at 15:31

thebtm

655411

answered Aug 17 at 15:31

thebtm

655411

answered Aug 17 at 15:31

thebtm

655411

655411

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
  – Stéphane Chazelas
  Aug 17 at 15:42
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
  – ilkkachu
  Aug 17 at 15:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Corrected to -P, sorry about that, i get the -E and -P mixed up
  – thebtm
  Aug 17 at 15:47
  

  
  
  
  

add a comment | 

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
  – Stéphane Chazelas
  Aug 17 at 15:42
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
  – ilkkachu
  Aug 17 at 15:44
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  Corrected to -P, sorry about that, i get the -E and -P mixed up
  – thebtm
  Aug 17 at 15:47
  

  
  
  
  

1

1

No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
– Stéphane Chazelas
Aug 17 at 15:42

No, with standard ERE, you can't escape the closing ] with backslash. backslash is not special inside bracket expressions. To have a ] inside a bracket expression, it needs to be first: other], not [ot]her]. That's different from PCREs which regex101 describe by default.
– Stéphane Chazelas
Aug 17 at 15:42

1

1

It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
– ilkkachu
Aug 17 at 15:44

It would work with pcregrep or GNU grep -P, though. And in a sense, the Perl behaviour is more straightforward: a backslash always makes a special character normal.
– ilkkachu
Aug 17 at 15:44

Corrected to -P, sorry about that, i get the -E and -P mixed up
– thebtm
Aug 17 at 15:47

Corrected to -P, sorry about that, i get the -E and -P mixed up
– thebtm
Aug 17 at 15:47

add a comment | 

 

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