10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Example data
$ ls *somehost*
10.10.10.10_somehost1.xyz.com.log
11.11.11.11_somehost2.xyz.com.log
#!/bin/bash
#FILES="*.log"
FILES=${FILES:-*.log}
for x in $FILES
do
ip="${x%%_*}" # isolate IP address
x="${x##*_}" # isolate hostname
hnam="${x%.*}" # Remove the ".log"... (2 Replies)
Discussion started by: popeye
2 Replies
2. Shell Programming and Scripting
I am trying to become more fluent with the interworking of bash and minimize the number of external calls.
Sample Data. This will be the response of the snmp query.
SNMPv2-MIB::sysName.0 = STRING: SomeHostName
SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises.9.1.1745... (5 Replies)
Discussion started by: sumguy
5 Replies
3. Shell Programming and Scripting
#!/bin/bash
SNMPW='/usr/bin/snmpwalk'
while read h i
do
loc=$($SNMPW -v3 -u 'Myusername' -l authPriv -a SHA -A 'Password1' -x AES -X 'Password2' $i sysLocation.0 2>/dev/null)
loc=${loc:-" is not snmpable."}
loc=${loc##*: }
loc=${loc//,/}
echo "$i,$h,$loc"
done < $1
My question is ... ... (1 Reply)
Discussion started by: sumguy
1 Replies
4. Shell Programming and Scripting
I have made the following examples that print various parameter expansions
text: iv-hhz-sac/hpac/hhz.d/iv.hpac..hhz.d.2016.250.070018.sac
(text%.*): iv-hhz-sac/hpac/hhz.d/iv.hpac..hhz.d.2016.250.070018
(text%%.*): iv-hhz-sac/hpac/hhz
(text#*.): d/iv.hpac..hhz.d.2016.250.070018.sac... (2 Replies)
Discussion started by: kristinu
2 Replies
5. UNIX for Dummies Questions & Answers
Hello experts,
I am exploring parameter expansion, and trying to cut the fields in a URL.
Following is the requirement:
I have
// abc.nnt /dir1/dir2/dir3/dir4/somefile.java
What i need to get is the path after dir3, and dir3 will be passed.
output that i need is... (1 Reply)
Discussion started by: gjarms
1 Replies
6. Shell Programming and Scripting
I'm trying to write a script that parses my music collection and hard link some filenames that my media player doesn't like to other names.
To do this I need to extract the name and remove alla non ASCII characters from that and do a cp -l with the result.
Problem is this:
22:16:58 $... (8 Replies)
Discussion started by: refuser
8 Replies
7. Shell Programming and Scripting
Hi -
I am trying to do a simple config file with known variable names in it, e.g.:
contents of config file a.conf: -a
-b $work
-c $host
simplified contents of bash script file: work='trunk'
host='alaska'
opts=$(tr '\n' ' ' < a.conf)
opts="$opts $*"
mycommand $opts arg1 arg2
The... (3 Replies)
Discussion started by: mrengert
3 Replies
8. Shell Programming and Scripting
Say you have this numeric variable that can be set by the user but you never want it to leave a certain range when it gets printed. How could you use parameter expansion such that it will never expand outside of that boundary? Thanks
---------- Post updated at 11:09 PM ---------- Previous update... (3 Replies)
Discussion started by: stevenswj
3 Replies
9. Shell Programming and Scripting
Hi ,
could anyone help me out with this problem.
sample.txt has this content :
u001- this is used for project1 ||
u002- this is used for p2|| not to be printed
u003- this is used
for project3 ||
u004- this is
used for p4 ||
u005- this is used for project5 ||
u006- this is used for p6... (9 Replies)
Discussion started by: Balaji PK
9 Replies
10. Shell Programming and Scripting
Hi all-
I have a variable that contains a web page:
echo $STUFF
<html> <head> <title>my page</title></head> <body> blah blah etc..
Can I use the shell's parameter expansion abilities to remove just the tags?
I thought that FIXHTML=${STUFF//<*>/} might do it, but it didn't seem to... (2 Replies)
Discussion started by: rev66
2 Replies
WORDEXP(3) Linux Programmer's Manual WORDEXP(3)
NAME
wordexp, wordfree - perform word expansion like a posix-shell
SYNOPSIS
#include <wordexp.h>
int wordexp(const char *s, wordexp_t *p, int flags);
void wordfree(wordexp_t *p);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
wordexp(), wordfree(): _XOPEN_SOURCE
DESCRIPTION
The function wordexp() performs a shell-like expansion of the string s and returns the result in the structure pointed to by p. The data
type wordexp_t is a structure that at least has the fields we_wordc, we_wordv, and we_offs. The field we_wordc is a size_t that gives the
number of words in the expansion of s. The field we_wordv is a char ** that points to the array of words found. The field we_offs of type
size_t is sometimes (depending on flags, see below) used to indicate the number of initial elements in the we_wordv array that should be
filled with NULLs.
The function wordfree() frees the allocated memory again. More precisely, it does not free its argument, but it frees the array we_wordv
and the strings that points to.
The string argument
Since the expansion is the same as the expansion by the shell (see sh(1)) of the parameters to a command, the string s must not contain
characters that would be illegal in shell command parameters. In particular, there must not be any unescaped newline or |, &, ;, <, >, (,
), {, } characters outside a command substitution or parameter substitution context.
If the argument s contains a word that starts with an unquoted comment character #, then it is unspecified whether that word and all fol-
lowing words are ignored, or the # is treated as a non-comment character.
The expansion
The expansion done consists of the following stages: tilde expansion (replacing ~user by user's home directory), variable substitution
(replacing $FOO by the value of the environment variable FOO), command substitution (replacing $(command) or `command` by the output of
command), arithmetic expansion, field splitting, wildcard expansion, quote removal.
The result of expansion of special parameters ($@, $*, $#, $?, $-, $$, $!, $0) is unspecified.
Field splitting is done using the environment variable $IFS. If it is not set, the field separators are space, tab and newline.
The output array
The array we_wordv contains the words found, followed by a NULL.
The flags argument
The flag argument is a bitwise inclusive OR of the following values:
WRDE_APPEND
Append the words found to the array resulting from a previous call.
WRDE_DOOFFS
Insert we_offs initial NULLs in the array we_wordv. (These are not counted in the returned we_wordc.)
WRDE_NOCMD
Don't do command substitution.
WRDE_REUSE
The argument p resulted from a previous call to wordexp(), and wordfree() was not called. Reuse the allocated storage.
WRDE_SHOWERR
Normally during command substitution stderr is redirected to /dev/null. This flag specifies that stderr is not to be redirected.
WRDE_UNDEF
Consider it an error if an undefined shell variable is expanded.
RETURN VALUE
In case of success 0 is returned. In case of error one of the following five values is returned.
WRDE_BADCHAR
Illegal occurrence of newline or one of |, &, ;, <, >, (, ), {, }.
WRDE_BADVAL
An undefined shell variable was referenced, and the WRDE_UNDEF flag told us to consider this an error.
WRDE_CMDSUB
Command substitution requested, but the WRDE_NOCMD flag told us to consider this an error.
WRDE_NOSPACE
Out of memory.
WRDE_SYNTAX
Shell syntax error, such as unbalanced parentheses or unmatched quotes.
VERSIONS
wordexp() and wordfree() are provided in glibc since version 2.1.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
+-----------+---------------+--------------------------------+
|Interface | Attribute | Value |
+-----------+---------------+--------------------------------+
|wordexp() | Thread safety | MT-Unsafe race:utent const:env |
| | | env sig:ALRM timer locale |
+-----------+---------------+--------------------------------+
|wordfree() | Thread safety | MT-Safe |
+-----------+---------------+--------------------------------+
In the above table, utent in race:utent signifies that if any of the functions setutent(3), getutent(3), or endutent(3) are used in paral-
lel in different threads of a program, then data races could occur. wordexp() calls those functions, so we use race:utent to remind users.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
EXAMPLE
The output of the following example program is approximately that of "ls [a-c]*.c".
#include <stdio.h>
#include <stdlib.h>
#include <wordexp.h>
int
main(int argc, char **argv)
{
wordexp_t p;
char **w;
int i;
wordexp("[a-c]*.c", &p, 0);
w = p.we_wordv;
for (i = 0; i < p.we_wordc; i++)
printf("%s
", w[i]);
wordfree(&p);
exit(EXIT_SUCCESS);
}
SEE ALSO
fnmatch(3), glob(3)
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/.
2017-09-15 WORDEXP(3)