XPost: alt.os.linux

In article <[email protected]>,
J.O. Aho <[email protected]> wrote:
...

Now instead !! is not rightly evaluated.
Why?

For in script you have the history expand by default disabled.

If you want it to be like in command line, then you need to enable the >history expand

--- bash script ---
#!/bin/bash
set -o history -o histexpand

ls /tmp > /dev/null
echo "CMD='"!:0"'"
--- eof ---

but it has it's bad sides as you see, you may use trap for better
debugging, but will not really works as you seems to want and I can't
see an user case where you would want to do your example.

Two comments:
1) OP has not stated what his actual goal is, so we don't know anything
about what the actual use case is. We may not ever hear back from
OP, so we are left guessing. At least one poster on the thread has
speculated that the goal is to capture the script name so that it
can be used to log file entries and so on. If that is the goal,
then there are many easier, better ways to do that.

2) OP might be looking for $_, which generally holds the name of the
last command executed (at least in bash; don't know about any other
shells). This works in scripts. I sometimes use $_ to tell me
whether or not a loop found a match (i.e., succeeded) or just ended
because the loop ended. For example:

for i in {list of files};do
[ $i matches or whatever ] && break
done
[ $_ = break ] && echo "A match was found!" || echo "Loop exited without finding a match"

--
Watching ConservaLoons playing with statistics and facts is like watching a newborn play with a computer. Endlessly amusing, but totally unproductive.

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XPost: alt.os.linux

Il 30/06/22 14:04, Kenny McCormack ha scritto:

OP has not stated what his actual goal is, so we don't know anything
about what the actual use case is.

$ tree dir | cat >> commands-output

After a few days (in which I will have forgotten what I did exactly, in
which I forgot the command I have in given...)

$ cat commands-output
dir
├── a
├── b
└── c

The output refers to what?
Or rather, Output refers to which command?

So at the first line I would have liked to have the reference command,
and then everything else.

Example

$ cat commands-output
REFERENCE COMMAND: $ tree dir
dir
├── a
├── b
└── c

It can be done?

-----BEGIN PGP MESSAGE-----

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=jI13
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XPost: alt.os.linux

Il 30/06/22 17:15, Lew Pitcher ha scritto:

[...]

$ rm typescript
$ echo "tree" | script | cat -n
1 Script iniziato, il file è typescript
2 tree
3 $ tree
4 .
5 ├── file1
6 ├── file2
7 └── typescript
8
9 0 directories, 3 files
10 $ exit
11 Script effettuato, il file è typescript
$ test -f typescript && echo FILE FOUND
FILE FOUND

I want to send the output only to the "cat -n" command and not to the typescript file.

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XPost: alt.os.linux

On Thu, 30 Jun 2022 16:50:25 +0200, Flash wrote:

Il 30/06/22 14:04, Kenny McCormack ha scritto:

OP has not stated what his actual goal is, so we don't know anything
about what the actual use case is.

$ tree dir | cat >> commands-output

UUOC. Try
tree dir >>commands-output
instead

After a few days (in which I will have forgotten what I did exactly, in
which I forgot the command I have in given...)

$ cat commands-output
dir
├── a
├── b
└── c

The output refers to what?
Or rather, Output refers to which command?

So at the first line I would have liked to have the reference command,
and then everything else.

[snip]

It can be done?

Yes

Try
echo "tree dir" | script -a commands-output

See script(1) ("man 1 script") for details

-----BEGIN PGP MESSAGE-----

[snip]

-----END PGP MESSAGE-----

And, why the encrypted message?

HTH
--
Lew Pitcher
"In Skills, We Trust"

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On 30.06.2022 14:04, Kenny McCormack wrote:

2) OP might be looking for $_, which generally holds the name of the
last command executed (at least in bash;

Does it? - In ksh $_ keeps the last word of the previous command line,
so 'break' or 'ls' will return the command name (incidentally), and
'ls a b c' will return 'c'. - A quick bash test seems to indicate that
it behaves like ksh in that respect.

don't know about any other
shells). This works in scripts. I sometimes use $_ to tell me
whether or not a loop found a match (i.e., succeeded) or just ended
because the loop ended. For example:

for i in {list of files};do
[ $i matches or whatever ] && break
done
[ $_ = break ] && echo "A match was found!" || echo "Loop exited without finding a match"

Wouldn't that be enough...?

for i in {list of files};do
[ $i matches or whatever ] && break
done && echo "A match was found!" || echo "Loop exited without finding a match"

(works at least in ksh)

Janis

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XPost: alt.os.linux

On 30/06/2022 16.50, Flash wrote:

Il 30/06/22 14:04, Kenny McCormack ha scritto:

 OP has not stated what his actual goal is, so we don't know anything
    about what the actual use case is.

$ tree dir | cat >> commands-output

After a few days (in which I will have forgotten what I did exactly, in
which I forgot the command I have in given...)

so you want something like:

--- runcmd ---
#!/bin/bash
CMD=$1
echo "$CMD"
eval $CMD
--- eof ---

runcmd "tree /dir" >> commands-output

Maybe better to bookmark the webpage where you found the command line in
the first place ;)

history is a good command to get to know what you done before and you
can add time stamp to it too

https://www.cyberciti.biz/faq/unix-linux-bash-history-display-date-time/

other alternatives:
- use more describing file names so you know what the content is and
how to regenerate it
- Use bash audit and look in the logs.
- make a script that does your work and can add a comment what input parameters was used


--
//Aho

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XPost: alt.os.linux

On Thu, 30 Jun 2022 18:15:02 +0200, Flash wrote:

[snip]

I want to send the output only to the "cat -n" command and not to the typescript file.

Ahhh. But that's /not/ what you said in the post I replied to

On Thu, 30 Jun 2022 16:50:25 +0200, Flash wrote:
Flash> $ tree dir | cat >> commands-output
Flash>
Flash> After a few days (in which I will have forgotten what I did exactly, in
Flash> which I forgot the command I have in given...)
...
Flash>
Flash> So at the first line I would have liked to have the reference command,
Flash> and then everything else.

You didn't say that you wanted the data line-numbered

Anyway, I answered the question you asked.
--
Lew Pitcher
"In Skills, We Trust"

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XPost: alt.os.linux

On Thu, 30 Jun 2022 16:50:25 +0200, Flash wrote:

Il 30/06/22 14:04, Kenny McCormack ha scritto:

OP has not stated what his actual goal is, so we don't know anything
about what the actual use case is.

$ tree dir | cat >> commands-output

After a few days (in which I will have forgotten what I did exactly, in
which I forgot the command I have in given...)

$ cat commands-output
dir
├── a
├── b
└── c

The output refers to what?
Or rather, Output refers to which command?

So at the first line I would have liked to have the reference command,
and then everything else.

Example

$ cat commands-output
REFERENCE COMMAND: $ tree dir
dir
├── a
├── b
└── c

It can be done?

(set -x; tree a) >commands-output 2>&1

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In article <t9kk0u$1v7i7$[email protected]>,
Janis Papanagnou <[email protected]> wrote:

On 30.06.2022 14:04, Kenny McCormack wrote:

2) OP might be looking for $_, which generally holds the name of the
last command executed (at least in bash;

Does it? - In ksh $_ keeps the last word of the previous command line,
so 'break' or 'ls' will return the command name (incidentally), and
'ls a b c' will return 'c'. - A quick bash test seems to indicate that
it behaves like ksh in that respect.

What can I say? It works for me.

Two comments:
1) The test should actually be:
[ X$_ = Xbreak ] && echo "It broke!"
since otherwise you have a problem if $_ is empty (which I think it
will be if you exit the loop "normally").

2) My actual use case was a little more complicated than the "distilled
down for posting to Usenet" version, and I was having problems
getting it to work reliably doing it your way. In general, I'm not
real comfortable with relying on "default" exit statuses (i.e.,
those not explicitly set in code).

But, anyway, it works for me. That's all that matters.

--
People who want to share their religious views with you
almost never want you to share yours with them. -- Dave Barry

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On 01.07.2022 18:12, Kenny McCormack wrote:

In article <t9kk0u$1v7i7$[email protected]>,
Janis Papanagnou <[email protected]> wrote:

On 30.06.2022 14:04, Kenny McCormack wrote:

2) OP might be looking for $_, which generally holds the name of the >>> last command executed (at least in bash;

Does it? - In ksh $_ keeps the last word of the previous command line,
so 'break' or 'ls' will return the command name (incidentally), and
'ls a b c' will return 'c'. - A quick bash test seems to indicate that
it behaves like ksh in that respect.

What can I say? It works for me.

I just wanted to point out that as soon as you have a command with
arguments it won't work any more; because the assumption that $_
would contain the command name was obviously wrong.

Two comments:
1) The test should actually be:
[ X$_ = Xbreak ] && echo "It broke!"
since otherwise you have a problem if $_ is empty (which I think it
will be if you exit the loop "normally").

2) My actual use case was a little more complicated than the "distilled
down for posting to Usenet" version, and I was having problems
getting it to work reliably doing it your way.

I considered that possibility, was sure you'll point that out if so.

In general, I'm not
real comfortable with relying on "default" exit statuses (i.e.,
those not explicitly set in code).

I see. Same here, but then I'd prefer setting and testing a flag
explicitly.

Janis

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XPost: alt.os.linux

Il 01/07/22 15:32, Joe Beanfish ha scritto:

(set -x; tree a) >commands-output 2>&1

buona idea

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