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Full Discussion: Understanding a regex
Top Forums Shell Programming and Scripting Understanding a regex Post 302603772 by vibhor_agarwali on Friday 2nd of March 2012 02:30:53 AM
Old 03-02-2012
Understanding a regex

Hi,

Please help me to understand the bold segments in the below regex.
Both are of same type whose meaning I am looking for.
Code:
find . \( -iregex './[0-9]\{6,10\}.[0-9]/src' \) -type d -maxdepth 2

Output:
Code:
./20111210.0/src

In continuation to above:
Code:
sed -e 's|./\([0-9]*.[0-9]\{1,3\}\).*|\1|g'

Output:
Code:
20111210.0

What I could gather:
In find it looks for directories starting with 0-9 followed by . (dot) & again the same pattern. Has a directory named src inside it.
The { confuses me.

In sed same thing.

---------- Post updated at 01:00 PM ---------- Previous update was at 12:42 PM ----------

Googling hints that it's probably the count.
Am I on right track?

Last edited by Franklin52; 03-02-2012 at 03:35 AM.. Reason: Please use code tags for code and data samples, thank you
 

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RE_COMP(3)						     Linux Programmer's Manual							RE_COMP(3)

NAME
re_comp, re_exec - BSD regex functions SYNOPSIS
#define _REGEX_RE_COMP #include <sys/types.h> #include <regex.h> char *re_comp(const char *regex); int re_exec(const char *string); DESCRIPTION
re_comp() is used to compile the null-terminated regular expression pointed to by regex. The compiled pattern occupies a static area, the pattern buffer, which is overwritten by subsequent use of re_comp(). If regex is NULL, no operation is performed and the pattern buffer's contents are not altered. re_exec() is used to assess whether the null-terminated string pointed to by string matches the previously compiled regex. RETURN VALUE
re_comp() returns NULL on successful compilation of regex otherwise it returns a pointer to an appropriate error message. re_exec() returns 1 for a successful match, zero for failure. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +---------------------+---------------+-----------+ |Interface | Attribute | Value | +---------------------+---------------+-----------+ |re_comp(), re_exec() | Thread safety | MT-Unsafe | +---------------------+---------------+-----------+ CONFORMING TO
4.3BSD. NOTES
These functions are obsolete; the functions documented in regcomp(3) should be used instead. SEE ALSO
regcomp(3), regex(7), GNU regex manual COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU
2017-09-15 RE_COMP(3)
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