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Issue 172

From Issue #172
August 2008

Aug 01, 2008  By Various
 in
The UpFront Section

UpFront

Tech Tip

If you often have multiple putty, terminal, ssh or screen sessions connected to various remote servers, one good way to organize them is to have a small script that places the name of the remote server in the title bar: 

#!/usr/bin/perl -w

$name = $ARGV[0];
unless ($name) { $name = `/bin/hostname` }
print "\033]0;$name\007";

Save this, and make it executable. If, for example, you save it as name, you simply can run name to place the name of the current server in the title bar of your current session.

If you want to label the session with something besides the hostname of the server, just specify the label on the command line: 

# name "Mail Server"

Tech Tip

Most Linux distros come packed with documentation in the /usr/share/doc directory, but rarely is there an easy way to get an overview of what's there. The following script creates a master index of all the index.html files in /usr/share/doc and outputs it as index.html in the user's home directory: 


#!/bin/bash

input_dir=/usr/share/doc
output_file=~/index.html

cat >$output_file <<EOF
<html>
<head>
<title>$input_dir</title>
</head>
<body>
EOF

find $input_dir -iname 'index.html' | \
    sed 's/[^ ]*/\<br\>\<a href="file:&"\>&\<\/a\>/' \
    >> $output_file

cat >>$output_file <<EOF
</body>
</html>
EOF

Tech Tip

The script command is used to log an entire session. Type the command script at the command prompt, and script then copies everything you type and its response to the file typescript. Script starts a sub-shell; when you want to stop saving the session, end the sub-shell (normally with Ctrl-D or by typing exit).

A very useful feature of the script command is that it can output timing information to a separate file. The script and the timing information then can be used to replay the script.

The following example creates a script and timing data (timing data is always written to standard error): 

$ script -t 2> timinginfo
Script started, file is typescript
$ ls
Desktop     test     scripts     redbooks
$ pwd
/home/jagadish
$ hostname
homepc
$ exit
exit
Script done, file is typescript

The entire terminal session then can be replayed later (with exact timing) using the scriptreplay command: 

$ scriptreplay timinginfo
$ ls
Desktop     test     scripts     redbooks
$ pwd
/home/jagadish
$ hostname
homepc
$ exit
exit

Script is a useful tool for training and educational purposes.

______________________

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