10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hey guys, my first post on UNIX Forums(much overdue IMO)!
I've got this bit of code that doesn't seem to be working correctly for an Android app I'm working on:
"screen -S gmod1 -p 0 -X stuff " & "" & command.text & "`echo -ne '\015'`"""
Basically it types command.text(variable determined... (4 Replies)
Discussion started by: stingwraith
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2. Shell Programming and Scripting
Greetings!
Here's what I believe is a "simple one" for the community tonight ;)
What I'm trying to do is assign a "true/false" value to a variable depending upon whether a named process (some-process) exists; and then test for this value in the succeeding logic. I banged my head against the... (2 Replies)
Discussion started by: LinQ
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3. Shell Programming and Scripting
hi all ,
i just tried to take the status of previous command inside the script using
echo $?. It throws me a variable syntax error , but when i use echo $? as an individual command it works perfectly .
can anyone Please tell me why am getting a variable syntax error when i use echo $?... (7 Replies)
Discussion started by: Rahul619
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4. Shell Programming and Scripting
$ cat data
Do NOT print me
START_MARKER
Print Me
END_MARKER
Do NOT print me
$ cat awk.sh
start=START_MARKER
end=END_MARKER
echo; echo Is this ugly syntax the only way?
awk '/'"$start"'/,/'"$end"'/ { print }' data
echo; echo Is there some modification of this that would work?
awk... (2 Replies)
Discussion started by: hanson44
2 Replies
5. Shell Programming and Scripting
first of all.. sorry about all the question bombing.. im bored atm so im currently playing around with sh scripting hehe
s = `expr ls -s Documents | grep Music | awk '{ print $1 }' `
t = `expr $t + $s`
it give syntax error
s not found
t not found lol...
any idea why? (7 Replies)
Discussion started by: Nick1097
7 Replies
6. Shell Programming and Scripting
Question: How I can change the shell option in my current environment, which I want to change the result of the command echo $-.
Background:
Special variable $-. It means the current shell option, and in my ENV, the result of this command as follows.
-bash-3.2$ echo $-
himBH
-bash-3.2$
... (2 Replies)
Discussion started by: ambious
2 Replies
7. Shell Programming and Scripting
Hi
I use awk command to delete the first blanc line of a file:
awk '/^$/ && !f{f=1;next}1' infile > outfile
can somebody please explain me what the last "1'" in !f{f=1;next}1' stands for... Thansk a lot -A (3 Replies)
Discussion started by: aoussenko
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8. UNIX for Dummies Questions & Answers
Hi,
Have to check file names in some given directory.
SO, What is the right syntax here:
*$3*=="'$object_list'" - just wanted to check if $3 is in the object_list.
And also, Do I need so many quotes around? (5 Replies)
Discussion started by: Leo_NN
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9. UNIX for Dummies Questions & Answers
I need some syntax help (working in a bash shell)
I have a variable which is a filename with an extension, and I need to create another variable with the same name but a different extension
To explain, the input file should be called something like "filename.L1" and the output file should be... (1 Reply)
Discussion started by: Slanter
1 Replies
10. Shell Programming and Scripting
How to export variables on a UNIX prompt. Please provide me syntax.
Thanks in advance.
Malay (5 Replies)
Discussion started by: malaymaru
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GETENV(3) BSD Library Functions Manual GETENV(3)
NAME
getenv, putenv, setenv, unsetenv -- environment variable functions
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
char *
getenv(const char *name);
int
setenv(const char *name, const char *value, int overwrite);
int
putenv(char *string);
int
unsetenv(const char *name);
DESCRIPTION
These functions set, unset and fetch environment variables from the host environment list.
The getenv() function obtains the current value of the environment variable, name. The application should not modify the string pointed to
by the getenv() function.
The setenv() function inserts or resets the environment variable name in the current environment list. If the variable name does not exist
in the list, it is inserted with the given value. If the variable does exist, the argument overwrite is tested; if overwrite is zero, the
variable is not reset, otherwise it is reset to the given value.
The putenv() function takes an argument of the form ``name=value'' and puts it directly into the current environment, so altering the argu-
ment shall change the environment. If the variable name does not exist in the list, it is inserted with the given value. If the variable
name does exist, it is reset to the given value.
The unsetenv() function deletes all instances of the variable name pointed to by name from the list.
If corruption (e.g., a name without a value) is detected while making a copy of environ for internal usage, then setenv(), unsetenv() and
putenv() will output a warning to stderr about the issue, drop the corrupt entry and complete the task without error.
RETURN VALUES
The getenv() function returns the value of the environment variable as a NUL-terminated string. If the variable name is not in the current
environment, NULL is returned.
The setenv(), putenv(), and unsetenv() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
ERRORS
[EINVAL] The function getenv(), setenv() or unsetenv() failed because the name is a NULL pointer, points to an empty string, or
points to a string containing an ``='' character.
The function putenv() failed because string is a NULL pointer, string is without an ``='' character or ``='' is the first
character in string. This does not follow the POSIX specification.
[ENOMEM] The function setenv(), unsetenv() or putenv() failed because they were unable to allocate memory for the environment.
SEE ALSO
csh(1), sh(1), execve(2), environ(7)
STANDARDS
The getenv() function conforms to ISO/IEC 9899:1990 (``ISO C90''). The setenv(), putenv() and unsetenv() functions conforms to IEEE Std
1003.1-2001 (``POSIX.1'').
HISTORY
The functions setenv() and unsetenv() appeared in Version 7 AT&T UNIX. The putenv() function appeared in 4.3BSD-Reno.
Until FreeBSD 7.0, putenv() would make a copy of string and insert it into the environment using setenv(). This was changed to use string as
the memory location of the ``name=value'' pair to follow the POSIX specification.
BUGS
Successive calls to setenv() that assign a larger-sized value than any previous value to the same name will result in a memory leak. The
FreeBSD semantics for this function (namely, that the contents of value are copied and that old values remain accessible indefinitely) make
this bug unavoidable. Future versions may eliminate one or both of these semantic guarantees in order to fix the bug.
BSD
June 20, 2007 BSD