I have been looking for this answer for a quite while but not exactly getting the right example or answer, that how can I run a script using a file as a parameter in linux I want to come up with something that if a user type for example this: # ./script.sh check1.txt in the bash so how it can automatically display the content of the file or make the appropriate script process. I am not sure whether I am explaining, right or wrong but this is the best I could. Give me any suggestions, examples or links. cheers.
this is pretty straight-forward, your script needs to use the command line arguments like this
# script.sh looks e.g. like this
infile=$1
second_param=$2
cat $infile > /tmp/$second_param
or whatever you like. then you call it like you expect:
./script.sh check1.txt
or
./script.sh check1.txt 123
if you need a second parameter
Related
I am writing a program with two inputs prog1 and prog2 which are both files. I save these two variables as program1 and program2 first and then execute these two files in my program using ./"$program1" and ./"program2", but the output is "No such file or directory" when i used ls to check the files are in the same directory as the script. Can anyone tell me how to execute it? thanks!
First, it seems like your brackets are out of place - ./"$program1" is not a valid expression, either loose the brackets or put it like this: "./$program1".
Then to elaborate a bit on David's comment:
There are two ways you can run another script from your script. One is to make them executable like David said.
However, you can also use the 'source' command to read and execute the content of files, even if they are not executable. So the following command would work in any case:
source "./$program1"
Instead of executing it as ./$prog1 execute it as below.
bash $prog1
bash $prog2
where $prog1 and $prog2 are variables which have the path of the bash scripts.
I'm trying to store the result of this command that is written in a script
ls -l /etc|wc -l
in a variable on another file.
To summarize, I have a script with that command and when I execute it, I want the result to be stored in a variable in another file.
Can someone help me with this please?
You may try to use temporary file (if possible).
This command:
ls -l /etc|wc -l > /tmp/myvar.txt
Another file:
myvar="$(cat /tmp/myvar.txt)"
You just need to use '> path/to/file' at the end of your command to redirect the output to a file (this will override the file content).
If you need another behavior, like append the content, you should use '>>' instead of '>'.
Take a look here for more details.
I'm not sure I understand what you're trying to do so I'll give you two solutions.
If the command you mention is in some file script_A.sh and you want the results of that script stored in some variable $var when running some other script script_B.sh, randomir's solution is good. In script_B:
var=$(bash path/to/script_A.sh)
If what you're asking is to run script_A.sh and then have it write a new line to a file that would store the results to a value when you run script_B.sh, I suppose you could run something like:
result=$(ls -l /etc|wc -l)
echo "var=\"$result\"" > path/to/script_B.sh
or even replace a line in a script_B.sh that already exists:
result= $(ls -l /etc|wc -l)
sed -i "s|var=SOMEPLACEHOLDER|var='$result'|" path/to/script_B.sh
If the latter is what you want, though, can you tell us more about what you're trying to accomplish? There's probably a better way than what you propose.
I am trying to run script on output files that can be further used as input files for gaussian.
I wanted to know what are the commands used in Linux to run the script on .log files and .HSCP1 files.
Many thanks,
Regards,
The generic syntax of passing an argument to a script in linux, assuming your script is named script.sh and your target file is named arg.log, would be
script.sh arg.log
This assigns the name arg.log to $1 inside the environment of the executing copy of script.sh. If you don't then do something with that, it won't matter.
You might also have your script read its stdin like this:
script.sh < arg.log
which will put the contents os arg.log on script.sh's stdin, but unless it reads them accordingly, it won't matter.
Of course, both these assume script.sh is in your $PATH; otherwise you will need to apply a path for the OS, such as /path/to/dir/with/script.sh or (if you are in the same directory) ./script.sh.
If what you are asking is how to get a lorge number of files assigned as arguments, you could pass wildcards - for the first example above, that could be done as
./script.sh /path/to/*.log /also/to/other.*
or you could use find, maybe with xargs like so -
find /path/to/files/ -name *.log | xargs /path/of/script.sh
which will call the script over and over.
I hope one of these helps, but you really must provide more context for what you are doing and how.
I have a problem regarding an alias file in /etc/profile.d/. This isn't anything important. I'm just interested why it isn't working as expected.
So basically I have the file 00-alias.sh at the path mentioned above and I wanted to make a shortcut which reads a specific line of a file. So this is my code:
alias lnn='sed -n "${1}p" < "${2}"'
With that code I should be able to perform a command like
$ lnn 4 test.txt
However, this doesn't work. I simply get the error
-bash: : No such file or directory
Now I thought, ok, maybe relative paths aren't working because the file is located at the path /etc/profile.d/00-alias.sh
So I went ahead and made a new alias like
alias pwd2='echo $(pwd)'
Then updated the profile.d with
source /etc/profile.d/00-alias.sh
And just tried pwd2 but that echoed the path I was currently in. So in theory the file can be found with the command I wrote. I still tried to pass the file to my alias with absolute path like
$ lnn 4 /var/test.txt
Still same error as above.
But, if I enter the command of the alias in the terminal like
sed -n "4p" < test.txt
It works perfectly fine. No matter if I put quotes around test.txt
And here is another weird thing: If I write
alias lnn='sed -n "${1}p" < ${2}'
without the quotes around ${2} I get the error
-bash: ${2}: ambiguous redirect
In the terminal it works just fine...
So, what am I doing wrong? Does anyone have an idea on this? I'd love to know my mistake. But as I said, this isn't a real problem as I'm just curious why bash behaves like that.
Aliases in bash do not take parameters of any form. Save the pain and use a function instead.
function lnn() {
sed -n "${1}p" < "${2}"
}
Add the function to the file 00-alias.sh and source it once before calling the function from command-line.
source /etc/profile.d/00-alias.sh
lnn 4 test.txt
See more information at BashFAQ/80: How can I make an alias that takes an argument?
You can't. Aliases in bash are extremely rudimentary, and not really suitable to any serious purpose. The bash man page even says so explicitly:
An excerpt from the GNU bash man page, about aliases
.. There is no mechanism for using arguments in the replacement text. If arguments are needed, a shell function should be used.
On a side note the problem has nothing to do with relative paths (or) so, just remember aliases are not allowed in scripts. They're only allowed in interactive shells. If you're writing a script, always use a function instead.
I am trying to create a script that will run a program on each file in a list. I have been trying to do this using a .csh file (I have no clue if this is the best way), and I started with something as simple as hello world
echo "hello world"
The problem is that I cannot execute this script, or verify that it works correctly. (I was trying to do ./testscript.csh which is obviously wrong). I haven't been able to find anything that really explains how to run C Scripts, and I'm guessing there's a better way to do this too. What do I need to change to get this to work?
You need to mark it as executable; Unix doesn't execute things arbitrarily based on extension.
chmod +x testscript.csh
Also, I strongly recommend using sh or bash instead of csh, or you will soon learn about the idiosyncrasies of csh's looping and control flow constructs (some things only work inside them if done a particular way, in particular with the single-line versions things are very limited).
You can use ./testscript.csh. You will however need to make it executable first:
chmod u+x testscript.csh
Which means set testscript to have execute permissions for the user (who ever the file is owned by - which in this case should be yourself!)
Also to tell the OS that this is a csh script you will need put
#! /path/to/csh
on the first line (where /path/to/csh is the full path to csh on your system. You can find that out by issuing the command which csh).
That should give you the behvaiour you want.
EDIT As discussed in some of the comments, you may want to choose an alternative shell to C Shell (csh). It is not the friendliest one for scripting.
You have several options.
You can run the script from within your current shell. If you're running csh or tcsh, the syntax is source testscript.csh. If you're running sh, bash, ksh, etc., the syntax is . ./testscript.sh. Note that I've changed the file name suffix; source or . runs the commands in the named file in your current shell. If you have any shell-specific syntax, this won't work unless your interactive shell matches the one used by the script. If the script is very simple (just a sequence of simple commands), that might not matter.
You can make the script an executable program. (I'm going to repeat some of what others have already written.) Add a "shebang" as the first line. For a csh script, use #!/bin/csh -f. The -f avoids running commands in your own personal startup scripts (.cshrc et al), which saves time and makes it more likely that others will be able to use it. Or, for a sh script (recommended), used #!/bin/sh (no -f, it has a completely different meaning). In either case, run chmod +x the_script, then ./the_script.
There's a trick I often use when I want to perform some moderately complex action. Say I want to delete some, but not all, files in the current directory, but the criterion can't be expressed conveniently in a single command. I might run ls > tmp.sh, then edit tmp.h with my favorite editor (mine happens to be vim). Then I go through the list of files and delete all the ones that I want to leave alone. Once I've done that, I can replace each file name with a command to remove it; in vim, :%s/.*/rm -f &/. I add a #!/bin/sh at the top save it, chmod +x foo.sh, then ./foo.sh. (If some of the file names might have special characters, I can use :%s/.*/rm -f '&'/.)