I am using pipes (specifically piping out) in Perl to put an array from one file into an array in a different file. I can't figure out how to transfer the array. I kow how to open the pipe : open (FILEHANDLE, "| file") or die~
but how do I transfer the array. I think it has something to do with... (1 Reply)
Hi, I am trying to write a program that will pipe any number of programs together like in the linux shell. As an example, the below code tries to execute "cat data | grep int | cut -b 1-10." The problem is that the programs never get executed for some reason. It seems like the first program... (3 Replies)
I've got a file with lots of commands I want to run in it. They're formatted like so:
cp /path/to/file /path/to/new/file
and on and on and on.
Hundreds of them.
Anyways, I'd like to execute them one at a time, then check what time it is, and repeat this process until 7am.
I can... (3 Replies)
Hi,
To explain this question I will have to go into a bit of detail. I hope you don't mind.
currently I have a log handler (an already compiled c++ version) and what it does is makes a log file and writes all the unix output (echo, etc) of a script to that log file. To me the log_handler is... (3 Replies)
Hi,
I'm trying to wrap my head around piping in C - I've got a small C program that forks and pipes stuff from the child process to the parent process.
Currently the child process calls a C program that squirts out random numbers which then pipes the result to the parent process.
The... (0 Replies)
Hi,
I need to use a double grep so to speak. I need to grep for a particular item say BOB and then for each successful result I need to grep for another item say SMITH.
I tried grep "BOB" filename | grep "SMITH"
but it does not seem to work.
I can achieve my desired result using an... (12 Replies)
Hi everybody,
I have a big file with blast results (if you know what this means, otherwise look at it just as a text file with a specific form).
I am trying to extract some ids from within this file, which have certain parameters.
For example, some Of my IDs have the term 'No hit results'... (1 Reply)
Hi ,
I have following code in my shell script :
"$TS_BIN/tranfrmr" "${TS_SETTINGS}/tranfrmr_p1.stx" "${TS_LOGS}/tranfrmr_p1.err" | (
"$TS_BIN/cusparse" "${TS_SETTINGS}/cusparse_p2.stx" "${TS_LOGS}/cusparse_p2.err" | (
"$TS_BIN/tsqsort" "${TS_SETTINGS}/srtforpm_p3.stx"... (8 Replies)
Hey guys. I'm very new to Unix. I'm pretty fluent in Java and C, but I have never actually used Unix for anything. I am in an Operating Systems course now and I have an assignment to write a piece of code that involves forks and piping. I'm stuck.
1. The problem statement, all variables and... (6 Replies)
Discussion started by: itsjimmy91
6 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)