How is Bash simple one line syntax to check and get the invalid or unrecognized command fed in shell or terminal prompt to be saved in a file? Illustration e.g.
$ run_bash_command FILE
$ foo
bash: foo: command not found
$ bar
bash: bar: command not found
$ baz
bash: baz: command not found
$ cat FILE
foo
bar
baz
With bash version >= 4.0 I suggest to add this function to ~/.bashrc and start a new session:
command_not_found_handle() {
echo "bash: $1: command not found" >&2;
echo "$#" >> /tmp/file.txt;
}
Related
Consider the following script
#!/bin/bash
abc
Here I want the "abc" cmd to be aliased to echo "Hi"(say)
But I don't have control to modify the script.
Is there a way to make the cmd behavior change without touching the script?
$ cat ./someScript.sh
#!/bin/bash
abc
$ ./someScript.sh
./someScript.sh: line 2: abc: command not found
Define a function named abc, and export it.
$ abc() { echo Hi; }
$ export -f abc
Now:
$ ./someScript.sh
Hi
I am messing around with shell scripts and I am trying to get my script to take input from another command, like say ls. It is called like this:
ls | ./example.sh
I try to access the input from within example.sh
#!/bin/bash
echo $1
but it echoes back nothing. Is there another way to reference parameters given to bash by other commands, because it works if I type in:
./example.sh poo
Parameters and input aren't the same thing:
$ ls
example.sh foo
$
$ cat example.sh
for param; do
printf 'argument 1: "%s"\n' "$param"
done
while IFS= read -t 1 -r input; do
printf 'input line: "%s"\n' "$input"
done
$
$ ls | ./example.sh
input line: "example.sh"
input line: "foo"
$
$ ls | ./example.sh bar
argument 1: "bar"
input line: "example.sh"
input line: "foo"
$
$ ./example.sh $(ls)
argument 1: "example.sh"
argument 1: "foo"
Parameters are the arguments passed to the script to start it running, input is what the script reads while it's running.
You can use xargs to do that.
ls | xargs ./example.sh
Resource
https://ss64.com/bash/xargs.html
https://www.cyberciti.biz/faq/linux-unix-bsd-xargs-construct-argument-lists-utility/
Or read man page for it
i have a bash script show below in a file called test.sh
#!/usr/bin/env bash
echo $1
echo "execution done"
when i execute this script using
Case-1
./test.sh "started"
started
execution done
showing properly
Case-2
If i execute with
bash test.sh "started"
i'm getting the out put as
started
execution done
But i would like to execute this using a cat or wget command with arguments
For example like.
Q1
cat test.sh |bash
Or using a command
Q2
wget -qO - "url contain bash" |bash
So in Q1 and Q2 how do i pass argument
Something simlar to this shown in this github
https://github.com/creationix/nvm
Please refer installation script
$ bash <(curl -Ls url_contains_bash_script) arg1 arg2
Explanation:
$ echo -e 'echo "$1"\necho "done"' >test.sh
$ cat test.sh
echo "$1"
echo "done"
$ bash <(cat test.sh) "hello"
hello
done
$ bash <(echo -e 'echo "$1"\necho "done"') "hello"
hello
done
You don't need to pipe to bash; bash runs as standard in your terminal.
If I have a script and I have to use cat, this is what I'll do:
cat script.sh > file.sh; chmod 755 file.sh; ./file.sh arg1 arg2 arg3
script.sh is the source script. You can replace that call with anything you want.
This has security implications though; just running an arbitrary code in your shell - especially with wget where the code comes from a remote location.
I am trying to run a command with a variable which holds another command that suppresses warning messages of the jar. However, it is not working as expected and I can't figure out what I am doing wrong.
TEST=${TEST:-2> /dev/null}
java -jar ~/bin/aw.jar ${Test}
Redirection is performed only if it is unquoted and present in the command line literally rather than originating from any kind of expansion:
$ ls
$ echo hello >out
$ ls
out
$ cat out
hello
$ rm *
$ echo hello '>out'
hello >out
$ ls
$ x='>out'
$ echo hello $x
hello >out
$ ls
In order to interpret redirection operator coming from a quoted string or an expansion you must execute the command through eval (note, however, that this may result in undesired expansions in other parts of your command):
$ ls
$ x='>out'
$ eval echo hello $x
$ ls
out
$ cat out
hello
Getting an error trying to call a function inside a process substitution.
Is there any way to do this?
#!/bin/bash
function testfunc
{
echo "bork"
}
diff <(testfunc) <(echo "bork")
The error is:
bork.sh: line 7: syntax error near unexpected token `('
bork.sh: line 7: `diff <(testfunc) <(echo "bork")'
--Update--
Problem was calling sh bork.sh, instead of bash ./bork.sh . Moral of the story make sure which shell you are executing with.
There's no problem here:
$ chmod +x test.sh
$ ./test.sh
Clear diff. No problem!
$ bash -x ./test.sh
+ diff /dev/fd/63 /dev/fd/62
++ testfunc
++ echo bork
++ echo bork
Proof that it worked
Troubleshooting:
Maybe you
run in a restricted shell
you don't have /dev/fd available/mounted correctly (due to somekind of secure chroot jail?)
The problem is probably that you're running the command with sh instead of bash.
$ cat > xx.sh
#!/bin/bash
function testfunc
{
echo "bork"
}
diff <(testfunc) <(echo "bork")
$ sh xx.sh
xx.sh: line 7: syntax error near unexpected token `('
xx.sh: line 7: `diff <(testfunc) <(echo "bork")'
$ bash xx.sh
$
The process substitution is not portable to the shell in /bin/sh. See the Bash manual on POSIX mode and bullet 28:
Process substitution is not available.
Tested on Mac OS X 10.10.5 (Yosemite).