Hi,
I am starting out to program on Unix, having had experience in C and C++ in DOS. I would like to know, of these three, which is the best book for learning C programming in Unix:
Advanced Unix Programming by Marc Rochkind
Advanced Unix Programming by Warren Gay
Advanced Programming in... (6 Replies)
hi ,
i am trying to compre two strings
if ] or if ]
when the length of var1 is small (around 300-400 char ) it works fine
but when it is large (around 900-1000 chars) it fails
is there any limitations for this type of comparison ??? (3 Replies)
hi ,
i am trying to compre two strings
if ] or if ]
when the length of var1 is small (around 300-400 char ) it works fine
but when it is large (around 900-1000 chars) it fails
is there any limitations for this type of comparison ??? (1 Reply)
I want to remove a line that has empty string at second field when I use cut with delimeter , like below
$cat demo
hello, mum
hello,
#!/bin/sh
while read line
do
if
then
# remove the current line command goes here
fi
done < "demo"
i got an error message for above... (4 Replies)
I Have a script which gets the status of oracle database and if the status is READ WRITE ..it should echo "db is up " else "db is down"
Here is the code
if
then
echo "db up"
else
echo "db down"
fi
done;
The script is giving me out put "db down" even thoug the value of... (6 Replies)
Hello everybody,
I decided to take a Unix Introduction class and have never had experience with programming. Everything was fine until recently when the Prof. started shell scripting and he wants us to make a small script to add unlimited numbers from arguments and from standard input.
I... (1 Reply)
Hello everybody,
I decided to take a Unix Introduction class and have never had experience with programming. Everything was fine until recently when the Prof. started shell scripting and he wants us to make a small script to add unlimited numbers from arguments and from standard input.
I... (8 Replies)
Hi,
can someone please help me!!! urgent!
I have a strange issue here. I grep for 2 strings from a txt files and compare the string value. Though the string values are the same, they are compared as different values. Please help
Case-1
--------
Here I grep for 2 different field values... (3 Replies)
guys , i am using inotify for monitoring one directory to check core file generation , my snippet of code is follows
#!/bin/bash
DIR=$1
inotifywait -q -e create -m $DIR | while read path events name;
do
if ]; then
echo "Now I am going to do something with $name in directory $path."... (5 Replies)
I have the logic below to look up for matches within the columns between the two files with awk.
In the if statement is where the string comparison is attempted with ==
The issue seems to be with the operands, as
1. when " '${SECTOR}' " -- double quote followed by single quote -- awk matches... (1 Reply)
Discussion started by: deadyetagain
1 Replies
LEARN ABOUT CENTOS
shell-quote
SHELL-QUOTE(1) User Contributed Perl Documentation SHELL-QUOTE(1)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 v5.16.3 2010-06-11 SHELL-QUOTE(1)