11-23-2002
eval in bash
hi everyone
i've been reading learning the bash and there is somrthing i don;t
understand what does eval do
i know that it run a command or script twice but i don;t see in
what for cases i can use this
could somebody explain this to me
9 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hi, experts.
Whould anybody clear explay me difference and usage of these 3 commands (particulary in bash) :
exec
eval
source
I've tryed to read the manual pages but did not get much.
Also could not get something useful from Google search - just so much and so not exactly, that is... (3 Replies)
Discussion started by: alex_5161
3 Replies
2. Shell Programming and Scripting
Hi All,
I'm running some encrypted data through a script I wrote. In order to do this, I'm using eval to resolve some of my variables. At the moment, when I use eval to resolve, it strips out some of my encrypted values, and totally drops some others. For example if I have the value ab1"3 it drops... (1 Reply)
Discussion started by: Khoomfire
1 Replies
3. Shell Programming and Scripting
I am trying to expand the variable $user in my alias command and tried
several variations of eval but can't seem to get it to work.
The end result should be either:
oracle_user='sudo su - oracle ' or oracle_user='sudo su - oracle1 '
user=$(grep '^oracle:' /etc/passwd | cut... (5 Replies)
Discussion started by: BeefStu
5 Replies
4. Shell Programming and Scripting
Hi all,
some small script with eval turned me to crazy.
my OS is linux
Linux s10-1310 2.6.16.53-0.8.PTF.434477.3.TDC.0-smp #1 SMP Fri Aug 31 06:07:27 PDT 2007 x86_64 x86_64 x86_64 GNU/Linux
below script works well
#!/bin/bash
eval ssh remotehost date
eval ssh remotehost ls
below... (1 Reply)
Discussion started by: summer_cherry
1 Replies
5. Shell Programming and Scripting
Hello All,
Since my variables are nested I use eval to populate the data.
I have an ambiguity here when eval is used along with &
say I have the below variable
url="www.unix.com" , this come from function call as argument.
I want to take this into another variable say... (6 Replies)
Discussion started by: sathyaonnuix
6 Replies
6. Shell Programming and Scripting
anyone has any info on why this is complaining???
vivek@vivek-c5e55ef2e ~/TAC
$ zoneCounter=1
vivek@vivek-c5e55ef2e ~/TAC
$ optUsage1=23%
vivek@vivek-c5e55ef2e ~/TAC
$ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>"
-bash: syntax error... (1 Reply)
Discussion started by: vivek d r
1 Replies
7. Shell Programming and Scripting
anyone has any info on why this is complaining???
vivek@vivek-c5e55ef2e ~/TAC
$ zoneCounter=1
vivek@vivek-c5e55ef2e ~/TAC
$ optUsage1=23%
vivek@vivek-c5e55ef2e ~/TAC
$ eval eval echo "<th>Zone $zoneCounter </th><th align=\"left\"> \$optUsage$zoneCounter </th>"
-bash: syntax error... (13 Replies)
Discussion started by: vivek d r
13 Replies
8. Shell Programming and Scripting
Hi,
I am running this on Redhat 5.10
I have a simple test script called test.sh which has the following
contents and it uses the BASH shebang.
-------------------------------------------------------------
#!/bin/bash
eval `/tmp/filereader.pl /tmp/envfile.txt`
echo "TESTPATH=$TESTPATH"
... (28 Replies)
Discussion started by: waavman
28 Replies
9. UNIX for Beginners Questions & Answers
Hi Guys,
I wrote a collection of bash functions years ago and now need to use them again but
I'm getting some error messages when eval tries to expand the variables names.
I recollect that I used the shopt command to set one of the options but I can't quite
remember the command that I... (8 Replies)
Discussion started by: ASGR
8 Replies
LEARN ABOUT OPENDARWIN
ldbash
LDBASH(1) libbash Manual LDBASH(1)
NAME
ldbash -- Dynamic loader for libbash(7) libraries.
SYNOPSIS
ldbash [-h | --help]
ldbash [-l | --list]
ldbash [-L | --load lib,[lib] ...]
ldbash [-U | --unload lib,[lib] ...]
ldbash [-e | --externlist lib,[lib] ...]
ldbash [--externlist-all]
ldbash [--i | --internlista lib,[lib] ...]
ldbash [--internlist-all]
DESCRIPTION
ldbash is used to manipulate libbash(7) libraries. Its main function is to load specific library. It can also print list of available
libraries, list functions each library exports, unload functions, etc.
In case of --load and --unload ,the output is intended to be passed to bash eval command.
Options
-h | --help Print options summary
-l | --list Display list of available libraries. The libraries names listed, may be passed as parameters to other invocations of ldbash.
I.e. first you run ldbash --list to see what is available and then you may load it.
-L | --load lib,[lib] ...
Load given libraries - i.e. print string that should be passed to eval command. Usually the string contains various source
commands.
Libraries that given libraries depend on are also loaded.
Libraries only loaded if their dependencies are satisfied. Dependencies are resolved using ldbash.cache file, which is created
by ldbashconfig(8).
-U | --unload lib,[lib] ...
Unload given libraries, but not their dependencies.
The output should be passed to eval command (in the same manner as with --load ).
-e | --externlist lib,[lib] ...
List all symbols that are exported by given libraries. Symbols are usually functions that given libraries implement.
--externlist-all
List all exported symbols of all available libraries. Symbols are usually functions that library implement.
-i | --internlist lib,[lib] ...
List all internal symbols (i.e. global variables/functions) of given libraries. This is intended mostly for developers that
want to develop library of their own, and want to be sure that they don't override any already defined symbol.
--internlist-all
List all internal symbols of all available libraries. This is intended mostly for developers that want to develop library of
their own, and want to be sure that they don't override any already defined symbol.
FILES
/etc/ldbash.cache
Cache file that contains information about libraries dependencies and list of exported symbols. See ldbashconfig((8)) for further
details.
BUGS
The script can't load libraries if their file name starts with '-'. (If someone uses file names that start with a '-' he/she deserves it!)
AUTHORS
Hai Zaar <haizaar@gmail.com>
Gil Ran <gil@ran4.net>
SEE ALSO
libbash(7), ldbashconfig(8)
Linux Epoch Linux