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Full Discussion: How to remove comments from a bash script?
Top Forums Shell Programming and Scripting How to remove comments from a bash script? Post 302660261 by LessNux on Friday 22nd of June 2012 09:21:20 AM
Old 06-22-2012
Question How to remove comments from a bash script?
I would like to remove comments from a bash script. In addition, I would like to remove lines that consist of only white spaces, and to remove blank lines.

Code:
#!/bin/bash
perl -pe 's/ *#.*$//g' $1 | grep -v ^[[:space:]]*$ | perl -pe 's/  +/ /g' > $2
#
# $1 INFILE
# $2 OUTFILE


The above code seemed to work at first. Unfortunately, however, I found later that the above code destroys the following two special variables.

${#ARRAY[@]} the number of array elements
$# the number of shell arguments

A workaround is to replace "${#" and "$#" with words that do not appear in the input file before applying the above code.


Code:
sed 's/${#/__UNUSUALWORD1__/g ; s/$#/__UNUSUALWORD2__/g' in.txt | \
perl -pe 's/ *#.*$//g' | grep -v ^[[:space:]]*$ | perl -pe 's/  +/ /g' | \
sed 's/__UNUSUALWORD1__/${#/ ; s/__UNUSUALWORD2__/$#/' > out.txt


However, the preparatory replacement is awkward. I would like to modify 's/ *#.*$//g' so that it will not match "${#" or "$#". Does anyone know a better solution?

Bash comments always start with #. However, the problem is that bash allows some exceptions where # does not lead a comment, as shown below.

Code:
${#ARRAY[@]} the number of array elements
$# the number of shell arguments
\# escaped by a backslash.
'abcd#efgh' protected by quotes
"abcd#efgh" protected by quotes

Does anyone know how to remove comments from bash scripts without destroying the exempted #'s that do not lead comments? (In addition, I would like to remove lines that consist of only white spaces, and to remove blank lines.)

Many thanks in advance.
Last edited by methyl; 06-22-2012 at 11:33 AM.. Reason: more code tags
 

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LEARN ABOUT SUSE

logprof.conf

LOGPROF.CONF(5) 						     AppArmor							   LOGPROF.CONF(5)

NAME

       logprof.conf - configuration file for expert options that modify the behavior of the AppArmor logprof(1) program.

DESCRIPTION

       The logprof(1) program can be configured to have certain default behavior by the contents of logprof.conf.

       The [qualifiers] section lists specific programs that should have a subset of the full ix/px/ux list when asking what mode to execute it
       using.

       Since creating a separate profile for /bin/bash is dangerous, we can specify that for /bin/bash, only (I)nherit, (U)nconstrained, and
       (D)eny should be allowed options and only those will show up in the prompt when we're asking about adding that to a profile.

       Likewise, if someone currently exec's /bin/mount in ix or px mode, things won't work, so we can provide only (U)nconstrained and (D)eny as
       options.

       And certain apps like grep, awk, sed, cp, and mkdir should always inherit the parent profile rather than having their own profile or
       running unconfined, so for them we can specify that only (I)nherit and (D)eny are the allowed options.

       Any programs that are not listed in the qualifiers section get the full (I)nherit / (P)rofile / (U)nconstrained / (D)eny option set.

       If the user is doing something tricky and wants different behavior, they can tweak or remove the corresponding line in the conf file.

       The [defaulthat] section lists changehat-aware programs and what hat logprof(1) will collapse the entries to for that program if the user
       specifies that the access should be allowed, but should not have it's own hat.

       The [globs] section allows modification of the logprof rule engine with respect to globbing suggestions that the user will be prompted
       with.

       The format of each line is-- "<perl glob> = <apparmor glob>".

       When logprof(1) asks about a specific path, if the perl glob matches the path, it replaces the part of the path that matched with the
       corresponding apparmor glob and adds it to the list of globbing suggestions.

       Lines starting with # are comments and are ignored.

EXAMPLE

	 [qualifiers]
	   # things will very likely be painfully broken if bash has it's own profile
	   /bin/bash  = iu

	   # mount doesn't work if it's confined
	   /bin/mount = u

	   # these helper utilities should inherit the parent profile and
	   # shouldn't have their own profiles
	   /bin/awk   = i
	   /bin/grep  = i
	   /bin/sed   = i

	 [defaulthat]
	   /usr/sbin/sshd	    = EXEC
	   /usr/sbin/httpd2	    = DEFAULT_URI
	   /usr/sbin/httpd2-prefork = DEFAULT_URI

	 [globs]
	   # /foo/bar/lib/libbaz.so -> /foo/bar/lib/lib*
	   /lib/lib[^/]+so[^/]*$  = /lib/lib*so*

	   # strip kernel version numbers from kernel module accesses
	   ^/lib/modules/[^/]+/   = /lib/modules/*/

	   # strip pid numbers from /proc accesses
	   ^/proc/d+/		    = /proc/*/

BUGS

       None. Please report any you find to bugzilla at <http://bugzilla.novell.com>.

SEE ALSO

       apparmor(7), apparmor.d(5), enforce(1), change_hat(2), complain(1), logprof(1), genprof(1), and
       <http://forge.novell.com/modules/xfmod/project/?apparmor>.

NOVELL
/SUSE							    2007-04-03							   LOGPROF.CONF(5)
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