Script to create a log file

satimis · 01-11-2006, 08:29 AM

Hi folks,

I need each command line typed on Console/Xterm window to be automatically copied to a file after hitting [ENTER] and the last "ten/x" lines of each corresponding output on the screen to be recorded on the file simultaneously. There are >300 comand lines to be executed. I'm building LFS-LinuxFromScratch. I only need the last "x" lines of the output on the screen to be recorded because on compilation maybe there are >10 pages of output. It serves as a log file.

I don't expect adding >file/>>file to the end of each command lines typed, if possible.

Please advise whether it is possible to run a shell script so that my requirement can be done. If YES, please advise how to prepare this shell script.

Is there another alternative to do it instead of running a shell script.

TIA

B.R.
satimis

ilikejam · 01-11-2006, 09:19 AM

Hi.

I'd probably just use the 'script' command to catch everything input and output to the terminal, then use a combination of grep -n, head and tail to parse the resulting log later. Doing this also means you have a full log, which might be more useful than just the last few lines of each command output.

Dave

satimis · 01-11-2006, 09:49 AM

Hi Dave,

Tks for your advice.

I haven't figured out how to make use of "script" and "grep -n" commands to do the job copying all typescript printed on the terminal and the corresponding output to a file. Could you please shed me some light.

e.g. on 3 command lines
- command line-1
- command line-2
- command line-3

File name = XYZ

TIA

B.R.
satimis

ilikejam · 01-11-2006, 11:21 AM

OK

If you run 'script' in a console, everything that is typed into, or output to the console gets recorded in a file called 'typescript' in your current directory. The 'man script' should describe it better than I can.

Once you've run your commands, do Ctrl-D to stop the 'script' command.

You can then look for the output of a particular command by grep'ing for your prompt and the name of the command, e.g. my command prompt looks like:

Code:

[0 dave@cronus ~]$

so if I was looking for the output of a command called 'multiburn', I would do:

Code:

grep -n 'dave@cronus' typescript | grep multiburn

the line number in the typescript file that command appears in would be shown as the number at the start of the line. You can look at the output of that command by jumping to that line number with

Code:

less +<lineNumber>g typescript

Dave

satimis · 01-12-2006, 01:06 AM

Hi Dave,

If I understand your advice correctly I shall perform following steps.

1)
To let typescript and screen output go to the file "xyz"

1a)
on console run;
# script /path/to/xyz

1b)
keyin the command lines

(remark:
I have to save "xyz" on the hard disc because I'm running LiveCD to build LFS. Otherwise once reboot all data saved will lose)

1c)
Ctrl-D to stop the 'script' command.

2)
To read info on "xyz"

2a)
To read the output of "command line-1"
# grep "command line-1" /path/to/xyz

2b)
To read line-210
# less +210g /path/to/xyz

If i'm wrong please correct me, tks.

Now I don't expect I can finish all commands in one day. On following day whether I have to run;

# script /path/to/xyz_2

Can I direct typescript of new command lines and screen output go to the same file "xyz" without overwriting previous content, i.e continue on the same file in following day.

TIA

B.R.
satimis

ilikejam · 01-12-2006, 07:17 AM

Hi again.

That looks just right.

You can add another session's output to xyz by using 'script -a /path/to/xyz' instead of 'script /path/to/xyz'

Dave

bigearsbilly · 01-12-2006, 07:45 AM

blimey, script, never knew that one.
excellent work.

satimis · 01-12-2006, 08:39 AM

Quote:

Originally Posted by ilikejam

You can add another session's output to xyz by using 'script -a /path/to/xyz' instead of 'script /path/to/xyz'

Hi Dave,

Noted with tks

BR
satimis

ilikejam · 01-13-2006, 06:41 AM

Cool. Enjoy.

Dave

satimis · 01-13-2006, 09:31 AM

Hi Dave,

I ran following test creating a file "lfs_notes_061113".
But it was an empty file. I think I made a misktake but could not discover the cause.

Test:
====

Started a LiveCD

root@4[/]# mount /dev/hda8 /mnt/hda8
root@4[/]# script /mnt/hda8/lfs_notes_061113

Code:

Script started, file is /mnt/hda8/lfs_notes_061113

sh-3.00# export LFS=/mnt/lfs
sh-3.00# mount -pv /dev/hda3 $LFS
sh-3.00# mkdir -v $LFS/home

Code:

mkdir: created directory ‘/mnt/lfs/home’

sh-3.00# mount -v /dev/hda5 $LFS/home

Code:

mount: you didn't specify a filesystem type for /dev/hda5
       I will try type ext3
/dev/hda5 on /mnt/lfs/home type ext3 (rw)

sh-3.00# echo $LFS

Code:

/mnt/lfs

sh-3.00# mkdir -v $LFS/tools

Code:

mkdir: created directory ‘/mnt/lfs/tools’

sh-3.00# ln -sv $LFS/tools /

Code:

create symbolic link ‘//tools’ to ‘/mnt/lfs/tools’

Here I started another console and mount /dev/hda8

root@6[/]# ls /mnt/hda8

Code:

lost+found
lfs_notes_061113

root@6[/]# nedit /mnt/hda8/lfs_notes_061113
It was an empty file

root@6[/]# du -sh /mnt/hda8/lfs_notes_061113

Code:

0       /mnt/hda8/lfs_notes_061113

Can you see which step I went wrong?

TIA

B.R.
satimis

ilikejam · 01-13-2006, 12:02 PM

Hi.

Yep. You have to do Ctrl-D (or 'exit') to finish the script session and write the file.

Dave

satimis · 01-14-2006, 09:42 AM

Hi Dave,

That means before executing "Ctrl+D" the file created is empty. If I need to read the history I must execute "Ctrl+D". To continue, run;
# script -a /path/to/file

and so on.

B.R.
satimis

ilikejam · 01-14-2006, 12:24 PM

If you run script with the '-f' option, it'll write to the file after each operation. That might be what you're after.

The 'script' man page is quite helpful ;-)

Dave

satimis · 01-16-2006, 06:18 AM

Hi Dave,

Your advice noted with tks.

On "man script"

Code:

...
......
     -c COMMAND
             Run the COMMAND rather than an interactive shell.  This makes it easy for a script to capture
             the output of a program that behaves differently when its stdout is not a tty.

     -f      Flush output after each write. This is nice for telecooperation: One person does `mkfifo foo;
             script -f foo' and another can supervise real-time what is being done using `cat foo'.

     -q      Be quiet.

     -t      Output timeing data to standard error. This data contains two fields, separated by a space.
             The first field indicates how much time elapsed since the previous output. The second field
             indicates how many characters were output this time. This information can be used to replay
             typescripts with realistic typing and output delays.
......

What will be the use of options - c, q and t ?

What shall I replace "COMMAND" on the command line to be run?

TIA

B.R.
satimis

ilikejam · 01-16-2006, 06:30 AM

-c would be used if you just want to run a single command (replace COMMAND with that command), or if the command you are running does something weird when it output isn't a terminal. Can't think of any examples of programs that do this, though. You could use this option to gather the output from commands if they're being run non-interactively, like from a shell script.

-q means it doesn't print the 'Script started, file is typescript' message at the start, or the message at the end.

-t prints (to std error, not std out) the time between keystrokes and outputs.

Dave