Actually it is the first two bytes and they inform the OS' program loader that the file is a script and that the remainder of the line specifies which command interpreter to run, with the script name as argument.
In addition it might be worth adding that only absolute pathes are allowed here. This:
will work, whereas
will not, even if ../../something would correctly resolve to the executable.
I am using an array (clmlist01). I have 61 of these and have 4 or more references to each one in a block of code that I do not want to have to hardcode. With that being said, I am creating a varible and going through a for loop to create the actually name of each array. The arrays would end up... (3 Replies)
I am facing a strange error while creating posix threads:
Given below are two snippets of code, the first one works whereas the second one gives a garbage value in the output.
Snippet 1
This works:
--------------
int *threadids;
threadids = (int *) malloc (num_threads * sizeof(int));
... (4 Replies)
Hello,
Please tell me if there is a better way to get the number of elements from an array that is passed to a function.
This is what works on Solaris 8 (ksh) but it looks odd:
loop_array() {
array_name=$2
b1='\${\#'
b2='}'
nr_elements=`eval echo... (6 Replies)
Hi,
What is the actual difference between these two? Why the following code works for process substitution and fails for command substitution?
while IFS= read -r line; do echo $line; done < <(cat file)executes successfully and display the contents of the file
But,
while IFS='\n' read -r... (3 Replies)
I've created a series of arrays named as follows:
row1
row2
row3
.
.
.
row10
Each has 4 elements.
I'm trying to echo the array elements out in a for loop. Here's what I have:
for ((i=1;i<=10;i++))
do
for ((j=1;j<=4;j++))
do
eval out=${row`echo $i`}
echo -n $out (3 Replies)
Hi.
I´ve a script that should substitude the 8th line in a file called xxx.num6.
The "xxx" is set by an array filled with this command:
j=0
for Par in *.sys ; do
Par=`echo $Par | sed 's/\(.*\).sys/\1/'` ;
Par2="$Par" ; echo "${Par2}"
j=$((j + 1));
done
Now i try... (0 Replies)
I have an array and two variables as below,
I need to check if $datevar is present in $filename.
If so, i need to replace $filename with the values in the array.
I need the output inside an ARRAY
How can this be done.
Any help will be appreciated. Thanks in advance. (2 Replies)
Trying to do some control flow parsing based on the index postion of an array member. Here is the pseudo code I am trying to write in (preferably in pure bash) where possible. I am thinking regex with do the trick, but need a little help.
pesudo code
if == ENDSINFIVEINTS ]]; then
do... (4 Replies)
Hi folks,
A really dumb question as I've wasted far too long trying to get this to work.... (on RH bash)
I have an array:
m0='<hello>'
m0='<there>'
m0='<fred>'
v0='<goodbye>'
v0='<again>'
v0='<john>'
in my code I calculate the value of the variable to output and if I echo it, I... (2 Replies)
hello,
i need a bit of help on how to do this effectively in bash without a lot of extra looping or massive switch/case
i have a long array of M elements and a short array of N elements, so M > N always. M is not a multiple of N.
for case 1, I want to stretch N to fit M
arrayHuge
H = (... (2 Replies)
Discussion started by: f77hack
2 Replies
LEARN ABOUT DEBIAN
shell-quote
SHELL-QUOTE(1p) User Contributed Perl Documentation SHELL-QUOTE(1p)NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$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)