12-23-2008
Relacing the shebang line of a file
Can any one tell me how to replace a shebang line of a file using sed?
Eg: If a file contains the following shebang line
#!C:/InstantRails/ruby/bin/ruby
I would like to replace it with
#!/usr/local/bin/ruby
The shebang line of the file can be obtained from the command
cat <filename> | head -1
and the replacing tag from the command "which ruby", since the shebang line contains many special characters, i guess the sed command is not working properly. Can anyone help me to replace the shebang line of a file using the
output of "which ruby"
Last edited by linuxnewbe; 12-23-2008 at 12:09 PM..
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IRB(1) Ruby Programmer's Reference Guide IRB(1)
NAME
irb -- Interactive Ruby Shell
SYNOPSIS
irb [--version] [-dfm] [-I directory] [-r library] [--[no]inspect] [--[no]readline] [--prompt mode] [--prompt-mode mode] [--inf-ruby-mode]
[--simple-prompt] [--noprompt] [--tracer] [--back-trace-limit n] [--irb_debug n] [--] [program_file] [argument ...]
DESCRIPTION
irb is the REPL(read-eval-print loop) environment for Ruby programs.
OPTIONS
--version Prints the version of irb.
-E external[:internal]
--encoding external[:internal]
Same as `ruby -E' . Specifies the default value(s) for external encodings and internal encoding. Values should be separated
with colon (:).
You can omit the one for internal encodings, then the value (Encoding.default_internal) will be nil.
-I path Same as `ruby -I' . Specifies $LOAD_PATH directory
-U Same as `ruby -U' . Sets the default value for internal encodings (Encoding.default_internal) to UTF-8.
-d Same as `ruby -d' . Sets $DEBUG to true.
-f Suppresses read of ~/.irbrc.
-h
--help Prints a summary of the options.
-m Bc mode (load mathn, fraction or matrix are available)
-r library Same as `ruby -r'. Causes irb to load the library using require.
--inspect Uses `inspect' for output (default except for bc mode)
--noinspect Doesn't use inspect for output
--readline Uses Readline extension module.
--noreadline Doesn't use Readline extension module.
--prompt mode
--prompt-mode mode
Switch prompt mode. Pre-defined prompt modes are `default', `simple', `xmp' and `inf-ruby'.
--inf-ruby-mode
Uses prompt appropriate for inf-ruby-mode on emacs. Suppresses --readline.
--simple-prompt
Makes prompts simple.
--noprompt No prompt mode.
--tracer Displays trace for each execution of commands.
--back-trace-limit n
Displays backtrace top n and tail n. The default value is 16.
--irb_debug n Sets internal debug level to n (not for popular use)
ENVIRONMENT
IRBRC
Also irb depends on same variables as ruby(1).
FILES
~/.irbrc Personal irb initialization.
EXAMPLES
% irb
irb(main):001:0> 1 + 1
2
irb(main):002:0> def t(x)
irb(main):003:1> x+1
irb(main):004:1> end
=> nil
irb(main):005:0> t(3)
=> 4
irb(main):006:0> if t(3) == 4
irb(main):007:1> p :ok
irb(main):008:1> end
:ok
=> :ok
irb(main):009:0> quit
%
SEE ALSO
ruby(1).
REPORTING BUGS
o Security vulnerabilities should be reported via an email to security@ruby-lang.org. Reported problems will be published after being
fixed.
o Other bugs and feature requests can be reported via the Ruby Issue Tracking System (http://bugs.ruby-lang.org). Do not report security
vulnerabilities via this system because it publishes the vulnerabilities immediately.
AUTHORS
Written by Keiju ISHITSUKA.
UNIX
November 15, 2012 UNIX