'Undefined variable' error when running tcsh script - linux

I am trying to execute each script that has "~SAC" at the end of their filenames. For such purpose, I wrote tc shell script using "foreach" like the code below.
However, when I execute it by typing ./run.tcsh, it only shows that
"tmpdir: Undefined variable". ('tmpdir' is the directory which has all the files which I want to apply my code)
How could I resolve this problem?
#!/bin/tcsh
set inputdir=tmpdir
foreach sacfile(`find $tmpdir -name '*.SAC'`)
echo "processing $sacfile"
classic_LR $sacfile
end
The name of my execution file is 'classic_LR' and it is executed by following form of input;
./classic_LR sacfile
where 'sacfile' refers to the name of file I want to apply classic_LR.

Your variable is inputdir and not tmpdir.
So, change
foreach sacfile(`find $tmpdir -name '*.SAC'`)
to
foreach sacfile(`find $inputdir -name '*.SAC'`)

Related

Running a loop for command and I want the output-name

I'm running a loop for command and I want the output-name to be result of concatenation of variable and a character.
I have the variable d (that is the name of the folder) and want to add S to the end of the output name for file1: d=file1 and I want the name of the output like this: file1S.
When I did -outdir "$d"s the name of the output is just s and I get error msg running the second file
Tell me if more clarification is needed.
Not sure if that's what you are looking for, but if you want to add an "s" to all of your files inside the directory, you can simply run the following loop:
for file in *; do mv $file ${file}s; done

Bash "file --mime-type" command is not working in Perl Script

I am trying to run bash commands inside Perl script. I am using system("file --mime-type $fileName); but it is not working while other commands are working such as ls or pwd.
In the terminal, it says "Cannot open 'Paper(filename)' (No such file or directory).
Below is my code:-
foreach my $a(#ARGV)
{
opendir(DIR, $a) or die "You've Passed Invalid Directory as Arguments or $!\n";
while(my $fileName = readdir DIR)
{
next if $fileName =~ /^\./; #this is to remove dotted hidden files.
system("file --mime-type $fileName");
print $fileName,"\n";
}
closedir(DIR);
}
Please see the screenshot of error message in terminal:
I am wondering why is this not working like other commands? When I type this command solely in terminal then it shows the file type correctly but not in the Perl script.
Some help will be highly appreciated.
$filename is just the filename, it doesn't include the directory portion. So file is looking for the file in your working directory, not the directory in $a.
You need to concatenate the directory name and filename to get a full pathname. Also, you should give a list of arguments to system(), since you're not using shell parsing.
system('file', '--mime-type', "$a/$fileName");

$_ variable in script does not work as expected

I have c shell script that sources another:
source ./sc1.csh param
the script being sourced does the following:
set scriptName=($_)
if ( "$scriptName" == "" ) then
set scriptName=$0
echo "#**E: Please source this script, DO NOT RUN!"
echo "ERROR"
exit 1
else
set scriptName=`basename $scriptName[2]`
endif
I expect $_ to contain "source ./sc1.csh param". However, it is actually empty. Manually running
source ./sc1.csh param
in the shell results in the correct, expected behavior.
What's going on?
Thanks.
From man csh
$_
Substitutes the command line of the last command executed. (+)
As the script has not completed execution yet, then $_ hasn't been set.
What happens if you call the script again?
Ok, so as user1717259 pointed out, $_ substitutes the command line of the last executed command, thus making it inappropriate for inspecting the command line inside the script being called. Instead, using $* (alias of $argv) works, as it contains all of the command line except for "source" itself.

Is it possible to write one script that runs in bash/shell and PowerShell?

I need to create ONE integrated script that sets some environment variables, downloads a file using wget and runs it.
The challenge is that it needs to be the SAME script that can run on both Windows PowerShell and also bash / shell.
This is the shell script:
#!/bin/bash
# download a script
wget http://www.example.org/my.script -O my.script
# set a couple of environment variables
export script_source=http://www.example.org
export some_value=floob
# now execute the downloaded script
bash ./my.script
This is the same thing in PowerShell:
wget http://www.example.org/my.script -O my.script.ps1
$env:script_source="http://www.example.org"
$env:some_value="floob"
PowerShell -File ./my.script.ps1
So I wonder if somehow these two scripts can be merged and run successfully on either platform?
I've been trying to find a way to put them in the same script and get bash and PowerShell.exe to ignore errors but have had no success doing so.
Any guesses?
It is possible; I don't know how compatible this is, but PowerShell treats strings as text and they end up on screen, Bash treats them as commands and tries to run them, and both support the same function definition syntax. So, put a function name in quotes and only Bash will run it, put "exit" in quotes and only Bash will exit. Then write PowerShell code after.
NB. this works because the syntax in both shells overlaps, and your script is simple - run commands and deal with variables. If you try to use more advanced script (if/then, for, switch, case, etc.) for either language, the other one will probably complain.
Save this as dual.ps1 so PowerShell is happy with it, chmod +x dual.ps1 so Bash will run it
#!/bin/bash
function DoBashThings {
wget http://www.example.org/my.script -O my.script
# set a couple of environment variables
export script_source=http://www.example.org
export some_value=floob
# now execute the downloaded script
bash ./my.script
}
"DoBashThings" # This runs the bash script, in PS it's just a string
"exit" # This quits the bash version, in PS it's just a string
# PowerShell code here
# --------------------
Invoke-WebRequest "http://www.example.org/my.script.ps1" -OutFile my.script.ps1
$env:script_source="http://www.example.org"
$env:some_value="floob"
PowerShell -File ./my.script.ps1
then
./dual.ps1
on either system.
Edit: You can include more complex code by commenting the code blocks with a distinct prefix, then having each language filter out its own code and eval it (usual security caveats apply with eval), e.g. with this approach (incorporating suggestion from Harry Johnston ):
#!/bin/bash
#posh $num = 200
#posh if (150 -lt $num) {
#posh write-host "PowerShell here"
#posh }
#bash thing="xyz"
#bash if [ "$thing" = "xyz" ]
#bash then
#bash echo "Bash here"
#bash fi
function RunBashStuff {
eval "$(grep '^#bash' $0 | sed -e 's/^#bash //')"
}
"RunBashStuff"
"exit"
((Get-Content $MyInvocation.MyCommand.Source) -match '^#posh' -replace '^#posh ') -join "`n" | Invoke-Expression
While the other answer is great (thank you TessellatingHeckler and Harry Johnston)
(and also thank you j-p-hutchins for fixing the error with true)
We can actually do way better
Work with more shells (e.g. work for Ubuntu's dash)
Less likely to break in future situations
No need to waste processing time re-reading/evaling the script
Waste less characters/lines on confusing syntax(we can get away with a mere 41 chars, and mere 3 lines)
Even Keep syntax highlighting functional
Copy Paste Code
Save this as your_thing.ps1 for it to run as powershell on Windows and run as shell on all other operating systems.
#!/usr/bin/env sh
echo --% >/dev/null;: ' | out-null
<#'
#
# sh part
#
echo "hello from bash/dash/zsh"
echo "do whatver you want just dont use #> directly"
echo "e.g. do #""> or something similar"
# end bash part
exit #>
#
# powershell part
#
echo "hello from powershell"
echo "you literally don't have to escape anything here"
How? (its actually simple)
We want to start a multi-line comment in powershell without causing an error in bash/shell.
Powershell has multi-line comments <# but as-is they would cause problems in bash/shell languages. We need to use a string like "<#" for bash, but we need it to NOT be a string in powershell.
Powershell has a stop-parsing arg --% lets write single quote without starting a string, e.g. echo --% ' blah ' will print out ' blah '. This is great because in shell/bash the single quotes do start a string, e.g. echo --% ' blah ' will print out blah
We need a command in order to use powershell's stop-parsing-args, lucky for us both powershell and bash have an echo command
So, in bash we can echo a string with <#, but powershell the same code finishes the echo command then starts a multi-line comment
Finally we add >/dev/null to bash so that it doesn't print out --% every time, and we add | out-null so that powershell doesn't print out >/dev/null;: ' every time.
The syntax highlighting tells the story more visually
Powershell Highlighting
All the green stuff is ignored by powershell (comments)
The gray --% is special
The | out-null is special
The white parts are just string-arguments without quotes
(even the single quote is equivlent to "'")
The <# is the start of a multi-line comment
Bash Highlighting
For bash its totally different.
Lime green + underline are the commands.
The --% isn't special, its just an argument
But the ; is special
The purple is output-redirection
Then : is just the standard "do nothing" shell command
Then the ' starts a string argument that ends on the next line
Caveats?
Almost almost none. Powershell legitimately has no downside. The Bash caveats are easy to fix, and are exceedingly rare
If you need #> in a bash string, you'll need to escape it somehow.
changing "#>" to "#"">"or from ' blah #> ' to ' blah #''> '.
If you have a comment #> and for some reason you CANNOT change that comment (this is what I mean by exceedingly rare), you can actually just use #>, you just have to add re-add those first two lines (eg true --% etc) right after your #> comment
One even more exceedingly rare case is where you are using the # to remove parts of a string (I bet most don't even know this is a bash feature). Example code below
https://man7.org/linux/man-pages/man1/bash.1.html#EXPANSION
var1=">blah"
echo ${var1#>}
# ^ removes the > from var1
To fix this one, well there are alternative ways of removeing chars from the begining of a string, use them instead.
Following up on Jeff Hykin's answer, I have found that the first line, while it is happy in bash, produces this output in PowerShell. Note that it is still fully functional, just noisy.
true : The term 'true' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling
of the name, or if a path was included, verify that the path is correct and try again.
At C:\Users\jp\scratch\envar.ps1:4 char:1
+ true --% ; : '
+ ~~~~
+ CategoryInfo : ObjectNotFound: (true:String) [], CommandNotFoundException
hello from powershell
I am experimenting with changing the first lines from:
true --% ; : '
<#'
to:
echo --% > /dev/null ; : ' | out-null
<#'
In very limited testing this seems to be working in bash and powershell. For reference, I am "sourcing" the scripts not "calling" them, e.g. . env.ps1 in bash and . ./env.ps1 in powershell.

Executing a bash script from a Perl program

I'm trying to write a Perl program which will execute a bash script. The Perl script looks like this
#!/usr/bin/perl
use diagnostics;
use warnings;
require 'userlib.pl';
use CGI qw(:standard);
ReadParse();
my $q = new CGI;
my $dir = $q->param('X');
my $s = $q->param('Y');
ui_print_header(undef, $text{'edit_title'}.$dir, "");
print $dir."<br>";
print $s."<br>";
print "Under Construction <br>";
use Cwd;
my $pwd = cwd();
my $directory = "/Logs/".$dir."/logmanager/".$s;
my $command = $pwd."/script ".$directory."/".$s.".tar";
print $command."<br>";
print $pwd."<br>";
chdir($directory);
my $pwd1 = cwd();
print $pwd1."<br>";
system($command, $directory) or die "Cannot open Dir: $!";
The script fail with the following error:
Can't exec "/usr/libexec/webmin/foobar/script
/path/filename.tar": No such file or directory at /usr/libexec/webmin/foobar/program.cgi line 23 (#3)
(W exec) A system(), exec(), or piped open call could not execute the
named program for the indicated reason. Typical reasons include: the
permissions were wrong on the file, the file wasn't found in
$ENV{PATH}, the executable in question was compiled for another
architecture, or the #! line in a script points to an interpreter that
can't be run for similar reasons. (Or maybe your system doesn't support #! at all.)
I've checked that the permissions are correct, the tar file I'm passing to my bash script exists, and also tried from the command line to run the same command I'm trying to run from the Perl script ( /usr/libexec/webmin/foobar/script /path/filename.tar ) and it works properly.
In Perl, calling system with one argument (in scalar context) and calling it with several scalar arguments (in list context) does different things.
In scalar context, calling
system($command)
will start an external shell and execute $command in it. If the string in $command has arguments, they will be passed to the call, too. So for example
$command="ls /";
system($commmand);
will evaluate to
sh -c "ls /"
where the shell is given the entire string, i.e. the command with all arguments. Also, the $command will run with all the normal environment variables set. This can be a security issue, see here and here for a few examples why.
On the other hand, if you call system with an array (in list context), Perl will not call a shell and give it the $command as argument, but rather try to execute the first element of the array directly and give it the other arguments as parameters. So
$command = "ls";
$directory = "/";
system($command, $directory);
will call ls directly, without spawning a shell in between.
Back to your question: your code says
my $command = $pwd."/script ".$directory."/".$s.".tar";
system($command, $directory) or die "Cannot open Dir: $!";
Note that $command here is something like /path/to/script /path/to/foo.tar, with the argument already being part of the string. If you call this in scalar context
system($command)
all will work fine, because
sh -c "/path/to/script /path/to/foo.tar"
will execute script with foo.tar as argument. But if you call it in list context, it will try to locate an executable named /path/to/script /path/to/foo.tar, and this will fail.
I found the problem.
changed the system command removing the second parameter and now it's working
system($command) or die "Cannot open Dir: $!";
In fairness I did not understand what was wrong on first example but now works fine, if anyone can explain probably it can be interesting understand
There are multiple ways to execute bash command/ scripts in perl.
System
backquate
exec

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