06-01-2010
executing a variable assignment in a string
I'm using whatever the scripting is in this copy of busybox ! So not the full boxed set sometimes.
If I do
cmd="echo fred"
$cmd
the system prints "fred"
if I do
cmd="fred=9"
$cmd
it barfs.
Is there a simple way to put a varabble assignment in a string and execute it?
David
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Hello Everybody,
Does anyone know what the @ symbol means in a csh script, if used with a variable assignment as below
@ line = 1
why not just use....
set line=1
Many thanks
rkap (1 Reply)
Discussion started by: rkap
1 Replies
2. Shell Programming and Scripting
I try to run this script, however, it gives an exception in line 3. How do I do an assignment to a substituted variable?
#!/bin/bash
name=fruit
ext_$(eval echo ${name})=apple
tmp=ext_$(eval echo ${name})
if ]; then
echo "apple"
elif ]; then
echo "orange"
fi
echo ${!tmp}
Error... (2 Replies)
Discussion started by: angelokh
2 Replies
3. Shell Programming and Scripting
Hi
I have variable A_B=alpha
also var1="A"
var2="B"
I want to retrieve the value alpha using var1 and var2 , somthing like
echo ${${var1}_${var2}} that works. Obviously this is receiving syntax
error (6 Replies)
Discussion started by: sumir
6 Replies
4. Shell Programming and Scripting
Hi:
I have a touble with executing a variable that stores a unix command string.
The following would be excuted fine:
command='ls -l'
`echo $command`
However, the following gives me an error:
command='(uuencode file1 file1; uuencode file2 file2) | mailx email_id'
`echo... (1 Reply)
Discussion started by: sagewise
1 Replies
5. Shell Programming and Scripting
Hi,
In AIX I have a variable with , (coma) separated values assigned to it like shown below
var1=apple,boy,chris
i want to convert this to
var1='apple','boy','chris'
the number of values assigned to var1 might change and it could be from 1 to n
any suggestions please? (3 Replies)
Discussion started by: rahul9909
3 Replies
6. Shell Programming and Scripting
Hi,
I have a requirement as follows, need to call the format of ${$var} form.
For example, i am taking a variable.
count=1,
((LIMIT_$count=$count + 1))
Now i have to echo this variable LIMIT_$count. (This is in a loop..)
echo ${LIMIT_$count} - displays as a syntax... (3 Replies)
Discussion started by: abhisheksunkari
3 Replies
7. Shell Programming and Scripting
for var in {1..3}
do
lspci -nn |awk -v i=$var '/8086:10a7/{split($1,a,""); print "0x"a}'
done
it will output
0x01
0x00
0x1
I want to let bus=0x01 slot=0x00 fun=0x1, How to modify this loop?
I know it can be get by
bus=`lspci -nn |awk... (4 Replies)
Discussion started by: yanglei_fage
4 Replies
8. Shell Programming and Scripting
guys,
i would like to know what does the below does.
tr=`echo $bfile | cut -d"." -f4`
tr=${tr#TR}
i tried with assigning a value and executed second line. but after that also value of tr remains same.
thanks in advance .. (1 Reply)
Discussion started by: expert
1 Replies
9. Shell Programming and Scripting
Hi
I have a strange problem:
In my shell script I am performing a copy task:
. prop.txt
cp -r $dir/ $dir/archive
$dir is fetched from a property file (prop.txt) which stores its value
dir=/opt/data
Now the problem is another dir1 comes into picture. I only want to add... (1 Reply)
Discussion started by: ankur328
1 Replies
10. Shell Programming and Scripting
Hi
I am facing a problem.
export local_folder=/opt/app/
cd /opt/app/abc/
abcversion="abc*" (abcga5 is inside /opt/app/abc/)
echo $abcversion (it echoes the correct version as abcga5 )
Now when I reuse the value of abcversion for a below path:
export... (6 Replies)
Discussion started by: ankur328
6 Replies
LEARN ABOUT CENTOS
trace-cmd-start
TRACE-CMD-START(1) TRACE-CMD-START(1)
NAME
trace-cmd-start - start the Ftrace Linux kernel tracer without recording
SYNOPSIS
trace-cmd start [OPTIONS]
DESCRIPTION
The trace-cmd(1) start enables all the Ftrace tracing the same way trace-cmd-record(1) does. The difference is that it does not run threads
to create a trace.dat file. This is useful just to enable Ftrace and you are only interested in the trace after some event has occurred and
the trace is stopped. Then the trace can be read straight from the Ftrace pseudo file system or can be extracted with trace-cmd-extract(1).
OPTIONS
The options are the same as trace-cmd-record(1), except that it does not take options specific to recording (-s, -o, -F, -N, and -t).
SEE ALSO
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-reset(1), trace-cmd-split(1),
trace-cmd-list(1), trace-cmd-listen(1)
AUTHOR
Written by Steven Rostedt, <rostedt@goodmis.org[1]>
RESOURCES
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
COPYING
Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).
NOTES
1. rostedt@goodmis.org
mailto:rostedt@goodmis.org
06/11/2014 TRACE-CMD-START(1)