Hmmm, may I object? Actually, bash also CAN "run the last segment of a pipeline in the current shell execution environment". man bash:
Quote:
shopt [-pqsu] [-o] [optname ...] lastpipe
If set, and job control is not active, the shell runs the last command of a pipeline not executed in the background in the current shell environment.
Hello guys.
In my script, i have the following code:
echo "The tarfile contains these directorys"
tar -tf file.tar > tarlist.txt
cat tarlist | awk -F/ '{print $1 "/" $2}' | nl
echo "Enter path of the directory you want to extract or just press enter to extract everything: "
read path... (1 Reply)
HI ,
I have to check the values of variable is blank or not.
exm :
###test
test1
var=`cate filename | head -1 | cut -c1-3`
I need to check the first three character of 1st line . if it is blank .then exit or we need to process .
Thanks in advance . (2 Replies)
I am testing a ksh script for email.
In the subject/content of the mail there is some dynamic variables like date and charges.
However these variables occupied the entire line erase other in that particular line
For e.g. there is a mail message:
This mail is intent...
Your total... (2 Replies)
Hi,
I am trying to execute a bunch of piped command which are stored in a variable, but only one command executed at a time, and rest of the pipes, commands and their arguments are considered as argument to the very first command.
Can you please help me in this?
bash-2.05$ cat test.sh... (1 Reply)
Hello everyone!
I am having an issue with a script I am trying to create.
I have an input file (named sort_$1.txt) like:
aaaa
bbbb
cccc
dddd
eeee
and I process it with the following code:
while read -r EachLine2
do (11 Replies)
Hi,
i am having one text file it contains some blank lines and i want to ignore that blank lines .
#! /bin/bash
clear
rdCount=0;
while read myline
do
echo $myline
let rdCount=$rdCount+1
done < ps.txt
echo "Total line=$rdCount"
and ps .txt contains the data- (17 Replies)
Hello, could you please help with this one. I have an input file like this:
123,4567,89000
123456789,9876543,12
and for the output I need strings to be with the fixed length, let's say 15, and if the string is -lt 15 to be populated with blanks at the end until it reach 15, like this:
123 ,4567... (1 Reply)
Hello All,
Maybe I'm Missing something here but I have NOOO idea what the heck is going on with this....?
I have a Variable that contains a PATTERN of what I'm considering "Illegal Characters". So what I'm doing is looping
through a string containing some of these "Illegal Characters". Now... (5 Replies)
Hi All,
I have a file which has hundred of records with fixed number of fields. In each record there is set of 8 characters which represent the duration of that activity. I want to sum up the duration present in all the records for a report. The problem is the duration changes per record so I... (5 Replies)
Hi,
I would like use the output of my cut command as a variable in my following awk command. Here's what I've written.
cut -f1 info.txt | awk -v i=xargs -F'' '{if($6 == $i) print $20}' summary.txt
Where obviously the 'xargs' doesn't do what I want. How can I pass my cut result to my awk... (3 Replies)
Discussion started by: heyooo
3 Replies
LEARN ABOUT CENTOS
shell-quote
SHELL-QUOTE(1) User Contributed Perl Documentation SHELL-QUOTE(1)NAME
shell-quote - quote arguments for safe use, unmodified in a shell command
SYNOPSIS
shell-quote [switch]... arg...
DESCRIPTION
shell-quote lets you pass arbitrary strings through the shell so that they won't be changed by the shell. This lets you process commands
or files with embedded white space or shell globbing characters safely. Here are a few examples.
EXAMPLES
ssh preserving args
When running a remote command with ssh, ssh doesn't preserve the separate arguments it receives. It just joins them with spaces and
passes them to "$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)