69

I want to grep smb.conf and see only lines which are not commented.

107
grep "^[^#;]" smb.conf

The first ^ refers to the beginning of the line, so lines with comments starting after the first character will not be excluded. [^#;] means any character which is not # or ;.

In other words, it reports lines that start with any character other than # and ;. It's not the same as reporting the lines that don't start with # and ; (for which you'd use grep -v '^[#;]') in that it also excludes empty lines, but that's probably preferable in this case as I doubt you care about empty lines.

If you wanted to ignore leading blank characters, you could change it to:

grep '^[[:blank:]]*[^[:blank:]#;]' smb.conf

or

grep -vxE '[[:blank:]]*([#;].*)?' smb.conf

Or

awk '$1 ~ /^[^;#]/' smb.conf
  • right answer is: cat /etc/samba/smb.conf | grep ^[^#\;] But anyway Thank you – denys Jan 11 '13 at 20:09
  • Yeah, or you could use "quotes"; I edited that in subsequently. – goldilocks Jan 11 '13 at 20:11
  • 7
    @denys You're wrong: goldilocks's response in not worst than your. .1 Please avoid using cat ...| syntax!. .2 For whipping empty lines AND lines containing only space, maybe with comments U could use this: grep -v "^ *\(#.*\|\)$" < smb.conf – F. Hauri Jan 11 '13 at 20:14
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    @EmanuelBerg It's an useless fork. cat file | grep "blah" implie running two binaries through a fifo, while grep "blah" <file do exactly same and bind file naturaly to grep's STDIN . [bash] useless cat is a full featured subject of search through any search engine! -> blog.sanctum.geek.nz/useless-use-of-cat ... for sample – F. Hauri Jan 11 '13 at 22:01
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    It doesn't do exactly the same. It creates 2 processes and a pipe where 1 process is enough. Read the link given in @F.Hauri's last comment. – rahmu Jan 11 '13 at 22:12
4

Vim solution:

:v/^\s*[#\n]/p

I stumbled across this question when trying to find the vim solution myself.

3

The pipe to grep in oliver nadj's answer may be eliminated by (assuming GNU grep or compatible):

grep -v "^\s*[#\;]\|^\s*$" <some_conf_file>
  • Second grep i@nadj's looks useless , @goldilocks's answer was more than eough. – Archemar Oct 13 '15 at 9:19
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    I agree that goldilocks's answer was correct. However, I also considered it useful to not show empty lines. – Morten Lind Oct 13 '15 at 17:41
2
grep -v "^\s*[#;]" any.conf | grep -v "^\s*$"

that is what works for me. ignore commented or empty lines, even whitespace before hash mark or semicolon

2

These examples might be of use to people.

[user@host tmp]$ cat whitespacetest
# Line 1 is a comment with hash symbol as first char

# Line 2 is a comment with hash symbol as second char
  # Line 3 is a comment with hash symbol as third char
        # Line 4 is a comment with tab first, then hash
        ; Line 5 is a comment with tab first, then semicolon. Comment char is ;
; Line 6 is a comment with semicolon symbol as first char
[user@host tmp]$

The first grep example excludes lines beginning with any amount of whitespace followed by a hash symbol.

[user@host tmp]$ grep -v '^[[:space:]]*#' whitespacetest

        ; Line 5 is a comment with tab first, then semicolon. Comment char is ;
; Line 6 is a comment with semicolon symbol as first char
[user@host tmp]$

The second excludes lines beginning with any amount of whitespace followed by a hash symbol or semicolon.

[user@host tmp]$ grep -v '^[[:space:]]*[#;]' whitespacetest

[user@host tmp]$
1

Here i got better one (assuming GNU grep or compatible):

grep -v '^[#;/%<]\|^\s*$' anyfile.conf

exclude for lines which begins with #;/%< which are in square brackets and the second filter after pipe is \s*$ for blank lines.

  • 1
    In what type of conf files are < or / used for comments? I know a lot of conf file formats where < is everything but a comment. ! is sometimes used like in X resource files. – Stéphane Chazelas Mar 16 '17 at 10:42
0
grep -v '^$\|^\s*#' temp

This one's a lot better, I got it from https://stackoverflow.com/questions/17392869/how-to-print-a-file-excluding-comments-and-blank-lines-using-grep-sed

It assumes GNU grep or compatible.

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