Questions -
1. In there , the magic is happening all because of $0=$2. Can someone please explain to me as to what does $0=$2 means ?
2. Also can someone go over the sed operation here as I tried to understand this for the past 2 hours and I am not getting anywhere with this.
my boss has done it again
I have been sent to fix a unix issue
and I ma hoping you can help
three issues
1st. I have a printer that when you try to print to it the print job comes out on a diffrent printer. If I take the printer ( dot matrix thourgh a serail connection) to a diffrent local the... (3 Replies)
I've a major file which includes other files and now I wanna 'cut' the file in several minor parts....like
....
find / -name "*.tmp" >filea
wc -l filea >fileb
sed -e '1s/ filea//' fileb >filec
AMOUNT=`cat filec`
if ; then
cat file a |head -100l (ell) |tail -100l >filec
cat file a |head... (6 Replies)
Hi All,
How can the head command be used to extract only a particular line.
By default head -n filename displays the first n lines. I want only the nth line.
I couldn't get it from forum search.
Thanks,
Sumesh (6 Replies)
I am new to UNIX......I have one file which contains thousnads of records with header and tailer.
Header
Record 1
Record 2
....
....
Last Record
Trailer
I want to concatenate Header and Trailer in the first line....now the output should look like this:
Header: Header value, Trailer:... (2 Replies)
$ct=1
head -n $ct file.
When i used like this, i got an error , Bad usage of head
Cant we use variables in place of number in HEAD.
In my requirement for every iteration i should increase the number in Head and tail the last one.
HOw can i achieve this (5 Replies)
Im looking for a 'relatively' easy way to search through cvs to look for a particular string in the HEAD revisions.
I realize the way CVS stores versions makes this difficult. But I'm trying to come up with some script to allow this search (performance is not expected here).
Currently this... (0 Replies)
I know that the common use of head is for example head -3 etc.Is there any possibility that,if i have a variable that equals to an integer(i=5),i can write head -i??
If not,what syntax or commands should i write down in order to have the same result?
//maybe something lik head -"$variable" ? (2 Replies)
i have lots of files in /law/prod and /law/dev, such as AP20PD, AP20WS, AP20.scr, AP20.rpt
if i am in /law DIR
find . -name AP20PD, found in /law/prod and /law/dev
i want to head -1 AP20PD from both location and >> /tmp/test.log
can i use find and head in one line ?
----------... (1 Reply)
Hi,
I need some advise on whether there is a better way of doing what I am currently planning to do. Perhaps I should be using arrays instead of re-directing output to files?
I need to use a tool/program named ADRCI provided by Oracle to remove trace files that it generates. Honestly it is... (1 Reply)
Discussion started by: newbie_01
1 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)