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 have a string of commands I am piping some data through and I want to allow command line switches to select which commands are used. I want to do something like this: OPTION="| command3"
command1 -a -b c.txt | command2 -d -e $OPTION >result.txt
I want to do it that way because OPTION may be... (1 Reply)
Im trying to check if a series of directory exists and if not create them, and am having issues. All the instances of test return with the error "test:
#!/bin/bash
location_Parent=~/Documents/sight_of_sound
location_IMG=~/Documents/Sight_of_sound/IMG
location_AUD=~/Documents/Sight_of_sound/AUD... (4 Replies)
In our shop, we have a situation where a log file from our interface engine software has begun maxing out in file size (reaching the 32-bit "2147483647" limit). Currently, the only way to rectify this is to stop the interface and restart it, which generates a new log. Easy enough, but the... (6 Replies)
Hi
I am trying to figure out what the following line does, I work in ksh88:
] && LIST="$big $LIST"
Not sure what "-a" means in that case.
Thanks a lot for any advice -A (1 Reply)
Hi,
I have line in input file as below:
3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL
My expected output for line in the file must be :
"1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL"
Can someone... (7 Replies)
Hello All,
Alright, so this is driving me absolutely insane. I can't seem to find this ANYWHERE...
I've tried every combination and synonym I can think of for this trying to search Google.
What is the Expect/Tcl equivalent to Perl and Bash's "=~" operator, (i.e. the "contains" operator).... (2 Replies)
How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address
and column 3 contains “cc” e-mail address to include with same email.
Sample input file, email.txt
Below is an sample code where... (2 Replies)
Hi!
I am having 02 files.
In first file" X" I am having 02 Columns
TCP-5100 Sybase_5100
TCP-5600 Sybase_5600
Second file "Y" for example--
:services (
:AdminInfo (
:chkpf_uid ("{A2F79713-B67D-4409-83A4-A90804E983E9}")
:ClassName (rule_services)
)
:compound ()... (12 Replies)
Hello.
System : opensuse leap 42.3
I have a bash script that build a text file.
I would like the last command doing :
print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt
where :
print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
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)