10-30-2013
Note:
-a may happen to be supported for historical reasons, however, it is not part of POSIX so
-e should be used instead.
Quote:
An early proposal used the KornShell -a primary (with the same meaning), but this was changed to -e because there were concerns about the high probability of humans confusing the -a primary with the -a binary operator.
test: Rationale
This User Gave Thanks to Scrutinizer For This Post:
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
#!/bin/sh
$ORACLE_HOME/bin/sqlplus -S $orauserid/$orapasswd@$oradb << _TMP
alter session set nls_date_format = 'YYYYMMDD HH24:MI';
set linesize 100
set pagesize 400
ok the above is part of a script..i just wanna know what does sqlplus -S means?? as in why we need to insert the -S behind? (2 Replies)
Discussion started by: forevercalz
2 Replies
2. AIX
. ${0%${0##*/}}Script_Name
if i issue this command, it is executing the script. can any one tell what is the meaning of ${0%${0##*/}} (7 Replies)
Discussion started by: nyelavarthy
7 Replies
3. UNIX for Dummies Questions & Answers
Can someone explain the use and meaning of "$*" expression. (2 Replies)
Discussion started by: sinpeak
2 Replies
4. UNIX for Dummies Questions & Answers
can some one please tell the meaning of the second statement i.e
n=${m#*=}
i couldnt get the meaning of the #*=
1.) m="mohit=/c/main/issue"
echo $m
result
-----------
mohit=/c/main/issue
2.) n=${m#*=}
echo $n
RESULT
-------
/c/main/issue (1 Reply)
Discussion started by: narang.mohit
1 Replies
5. Shell Programming and Scripting
can someone please tell what !* means in shell syntax.
Regards, (3 Replies)
Discussion started by: busyboy
3 Replies
6. HP-UX
Executed the following if conditions .. and got different results .
only (( )) gave correct o/p with all scenarios .
Can anybody please let me know what is the difference between and ] and ((condition)) when used with if condition.
And why each condition gave different result.
1.... (2 Replies)
Discussion started by: soumyabubun
2 Replies
7. UNIX for Dummies Questions & Answers
Hi all,
I wanna know the meaning of the last word "<<! "
sudo su - user <<!
please help on this !!!! (1 Reply)
Discussion started by: sudharson
1 Replies
8. Shell Programming and Scripting
hi,
I have some problems in my simple script about the redirect echo stdout command inside a condition. Why is the echo command inside the elif still execute in the else command
Here are my simple script
After check on the two diff output the echo stdout redirect is present in two diff... (3 Replies)
Discussion started by: jao_madn
3 Replies
9. Shell Programming and Scripting
HI
My doubt may be basic one but I need to get it clarified..
When i use "if" condition that checks for many AND, OR logical conditions
like
if ]; then
return 0
fi
Even the if condition fails it returns as zero.. Any clue..
But if i add else condition like
if ]; ... (2 Replies)
Discussion started by: Priya Amaresh
2 Replies
10. Shell Programming and Scripting
Hello everyone,
I'm looking for the meaning of this expression, as I don't understand it quite clearly : $1^
What do you think it could be?
I thought either:
- match lines starting with argument 1 but it should be ^$1
- turn line around : word becomes drow
Thanks in advance for your... (4 Replies)
Discussion started by: bibelo
4 Replies
LEARN ABOUT DEBIAN
shell-quote
SHELL-QUOTE(1p) User Contributed Perl Documentation SHELL-QUOTE(1p)
NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$SHELL -c". This doesn't work as intended:
ssh host touch 'hi there' # fails
It creates 2 files, hi and there. Instead, do this:
cmd=`shell-quote touch 'hi there'`
ssh host "$cmd"
This gives you just 1 file, hi there.
process find output
It's not ordinarily possible to process an arbitrary list of files output by find with a shell script. Anything you put in $IFS to
split up the output could legitimately be in a file's name. Here's how you can do it using shell-quote:
eval set -- `find -type f -print0 | xargs -0 shell-quote --`
debug shell scripts
shell-quote is better than echo for debugging shell scripts.
debug() {
[ -z "$debug" ] || shell-quote "debug:" "$@"
}
With echo you can't tell the difference between "debug 'foo bar'" and "debug foo bar", but with shell-quote you can.
save a command for later
shell-quote can be used to build up a shell command to run later. Say you want the user to be able to give you switches for a command
you're going to run. If you don't want the switches to be re-evaluated by the shell (which is usually a good idea, else there are
things the user can't pass through), you can do something like this:
user_switches=
while [ $# != 0 ]
do
case x$1 in
x--pass-through)
[ $# -gt 1 ] || die "need an argument for $1"
user_switches="$user_switches "`shell-quote -- "$2"`
shift;;
# process other switches
esac
shift
done
# later
eval "shell-quote some-command $user_switches my args"
OPTIONS
--debug
Turn debugging on.
--help
Show the usage message and die.
--version
Show the version number and exit.
AVAILABILITY
The code is licensed under the GNU GPL. Check http://www.argon.org/~roderick/ or CPAN for updated versions.
AUTHOR
Roderick Schertler <roderick@argon.org>
perl v5.8.4 2005-05-03 SHELL-QUOTE(1p)