Mencoder-users Fresh Build Recommendations, Scripts For Mac

15 FFMPEG Command Examples in Linux For more details about FFmpeg and steps to install it in different Linux distros, read the article from the link below: Useful FFmpeg Commands FFmpeg utility supports almost all major audio and video formats, if you want to check the ffmpeg supported available formats you can use./ffmpeg -formats command to list all supported formats. If you are new to this tool, here are some handy commands that will give you a better idea about the capabilities of this powerful tool. Get Video File Information To get information about a file (say video.mp4), run the following command. Remember you have to specify an ouput file, but in this case we only want to get some information about the input file. $ ffmpeg -i video.flv -hidebanner. Split Video into Images After successful execution of above command you can verify that the video turn into multiple images using following.

• Mencoder-users Fresh Build Recommendations Scripts For Mac Pro

I used it ages ago to produce movies from simulation snapshots. Way back then, it could read a sequence of PDB files, render them (or generate POV-Ray scripts to raytrace them), and store them as individual images. I then used mencoder to generate MPEG-4 files out of the stills. Those were the days.

Add Image to Audio 15. Add subtitles to a Movie If you have a separate subtitle file called subtitle.srt, you can use following command to add subtitle to a movie file: $ ffmpeg -i video.mp4 -i subtitles.srt -map 0 -map 1 -c copy -c:v libx264 -crf 23 -preset veryfast video-output.mkv Summary That is all for now but these are just few examples of using FFmpeg, you can find more options for what you wish to accomplish. Remember to post a comment to provide information about how to use FFmpeg or if you have encountered errors while using it.

This tutorial assumes no previous knowledge of scripting or programming, yet progresses rapidly toward an intermediate/advanced level of instruction. All the while sneaking in little nuggets of UNIX® wisdom and lore. It serves as a textbook, a manual for self-study, and as a reference and source of knowledge on shell scripting techniques.

The exercises and heavily-commented examples invite active reader participation, under the premise that the only way to really learn scripting is to write scripts. This book is suitable for classroom use as a general introduction to programming concepts. This document is herewith granted to the Public Domain.

No copyright! Dedication For Anita, the source of all the magic. List of Examples 2-1. Script: A writing; a written document. Obs.

Mencoder-users Fresh Build Recommendations Scripts For Mac Pro

Webster's Dictionary, 1913 ed. The shell is a command interpreter.

More than just the insulating layer between the operating system kernel and the user, it's also a fairly powerful programming language. A shell program, called a script, is an easy-to-use tool for building applications by 'gluing together' system calls, tools, utilities, and compiled binaries. Virtually the entire repertoire of UNIX commands, utilities, and tools is available for invocation by a shell script.

If that were not enough, internal shell commands, such as testing and loop constructs, lend additional power and flexibility to scripts. Shell scripts are especially well suited for administrative system tasks and other routine repetitive tasks not requiring the bells and whistles of a full-blown tightly structured programming language. Shell Programming! No programming language is perfect. There is not even a single best language; there are only languages well suited or perhaps poorly suited for particular purposes.Herbert Mayer A working knowledge of shell scripting is essential to anyone wishing to become reasonably proficient at system administration, even if they do not anticipate ever having to actually write a script. Consider that as a Linux machine boots up, it executes the shell scripts in /etc/rc.d to restore the system configuration and set up services. A detailed understanding of these startup scripts is important for analyzing the behavior of a system, and possibly modifying it.

The craft of scripting is not hard to master, since scripts can be built in bite-sized sections and there is only a fairly small set of shell-specific operators and options to learn. The syntax is simple - even austere - similar to that of invoking and chaining together utilities at the command line, and there are only a few 'rules' governing their use. Most short scripts work right the first time, and debugging even the longer ones is straightforward. In the early days of personal computing, the BASIC language enabled anyone reasonably computer proficient to write programs on an early generation of microcomputers. Decades later, the Bash scripting language enables anyone with a rudimentary knowledge of Linux or UNIX to do the same on modern machines. We now have miniaturized single-board computers with amazing capabilities, such as the.

Bash scripting provides a way to explore the capabilities of these fascinating devices. A shell script is a quick-and-dirty method of prototyping a complex application.

Getting even a limited subset of the functionality to work in a script is often a useful first stage in project development. In this way, the structure of the application can be tested and tinkered with, and the major pitfalls found before proceeding to the final coding in C, C, Java, or Python. Shell scripting hearkens back to the classic UNIX philosophy of breaking complex projects into simpler subtasks, of chaining together components and utilities. Many consider this a better, or at least more esthetically pleasing approach to problem solving than using one of the new generation of high-powered all-in-one languages, such as Perl, which attempt to be all things to all people, but at the cost of forcing you to alter your thinking processes to fit the tool. According to, 'a useful language needs arrays, pointers, and a generic mechanism for building data structures.'

By these criteria, shell scripting falls somewhat short of being 'useful.' Or, perhaps not. Cleanup: A script to clean up log files in /var/log # Cleanup # Run as root, of course. Cd /var/log cat /dev/null messages cat /dev/null wtmp echo 'Log files cleaned up.' There is nothing unusual here, only a set of commands that could just as easily have been invoked one by one from the command-line on the console or in a terminal window. The advantages of placing the commands in a script go far beyond not having to retype them time and again. The script becomes a program - a tool - and it can easily be modified or customized for a particular application.

Cleanup: An improved clean-up script #!/bin/bash # Proper header for a Bash script. # Cleanup, version 2 # Run as root, of course. # Insert code here to print error message and exit if not root. LOGDIR=/var/log # Variables are better than hard-coded values. Cd $LOGDIR cat /dev/null messages cat /dev/null wtmp echo 'Logs cleaned up.'

Exit # The right and proper method of 'exiting' from a script. # A bare 'exit' (no parameter) returns the exit status #+ of the preceding command. Now that's beginning to look like a real script. But we can go even farther.

This tutorial encourages a modular approach to constructing a script. Make note of and collect 'boilerplate' code snippets that might be useful in future scripts. Eventually you will build quite an extensive library of nifty routines.

As an example, the following script prolog tests whether the script has been invoked with the correct number of parameters. EWRONGARGS=85 scriptparameters='-a -h -m -z' # -a = all, -h = help, etc. If $# -ne $Numberofexpectedargs then echo 'Usage: `basename $0` $scriptparameters' # `basename $0` is the script's filename. Exit $EWRONGARGS fi Many times, you will write a script that carries out one particular task. The first script in this chapter is an example. Later, it might occur to you to generalize the script to do other, similar tasks. Replacing the literal ( 'hard-wired') constants by variables is a step in that direction, as is replacing repetitive code blocks.

Either: chmod 555 scriptname (gives everyone read/execute permission) or chmod +rx scriptname (gives everyone read/execute permission) chmod u+rx scriptname (gives only the script owner read/execute permission) Having made the script executable, you may now test it by./scriptname. If it begins with a 'sha-bang' line, invoking the script calls the correct command interpreter to run it. As a final step, after testing and debugging, you would likely want to move it to /usr/local/bin (as root, of course), to make the script available to yourself and all other users as a systemwide executable.

The script could then be invoked by simply typing scriptname ENTER from the command-line. Lines beginning with a # (with the exception of ) are comments and will not be executed. # This line is a comment. Comments may also occur following the end of a command. Echo 'A comment will follow.'

# Comment here. # ^ Note whitespace before # Comments may also follow at the beginning of a line. # A tab precedes this comment. Comments may even be embedded within a. Initial=( `cat '$startfile' sed -e '/#/d' tr -d ' n' # Delete lines containing '#' comment character. Sed -e 's/./.

/g' -e 's// /g'` ) # Excerpted from life.sh script. 'dot', as a component of a filename. When working with filenames, a leading dot is the prefix of a 'hidden' file, a file that an will not normally show. A pipe, as a classic method of interprocess communication, sends the stdout of one to the stdin of another.

In a typical case, a command, such as or, pipes a stream of data to a filter, a command that transforms its input for processing. Cat $filename1 $filename2 grep $searchword For an interesting note on the complexity of using UNIX pipes, see. The output of a command or commands may be piped to a script. #!/bin/bash # uppercase.sh: Changes input to uppercase.

Tr 'a-z' 'A-Z' # Letter ranges must be quoted #+ to prevent filename generation from single-letter filenames. Exit 0 Now, let us pipe the output of ls -l to this script. Bash$ ls -l./uppercase.sh -RW-RW-R- 1 BOZO BOZO 109 APR 7 19:49 1.TXT -RW-RW-R- 1 BOZO BOZO 109 APR 14 16:48 2.TXT -RW-R-R- 1 BOZO BOZO 725 APR 20 20:56 DATA-FILE. The stdout of each process in a pipe must be read as the stdin of the next.

If this is not the case, the data stream will block, and the pipe will not behave as expected. Cat file1 file2 ls -l sort # The output from 'cat file1 file2' disappears. A pipe runs as a, and therefore cannot alter script variables. Variable='initialvalue' echo 'newvalue' read variable echo 'variable = $variable' # variable = initialvalue If one of the commands in the pipe aborts, this prematurely terminates execution of the pipe. Called a broken pipe, this condition sends a SIGPIPE. Running a loop in the background #!/bin/bash # background-loop.sh for i in 1 2 3 4 5 6 7 8 9 10 # First loop.

Do echo -n '$i ' done & # Run this loop in background. # Will sometimes execute after second loop. Echo # This 'echo' sometimes will not display. For i in 11 12 13 14 15 16 17 18 19 20 # Second loop.

Do echo -n '$i ' done echo # This 'echo' sometimes will not display. # # The expected output from the script: # 1 2 3 4 5 6 7 8 9 10 # 11 12 13 14 15 16 17 18 19 20 # Sometimes, though, you get: # 11 12 13 14 15 16 17 18 19 20 # 1 2 3 4 5 6 7 8 9 10 bozo $ # (The second 'echo' doesn't execute. Why?) # Occasionally also: # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 # (The first 'echo' doesn't execute. Why?) # Very rarely something like: # 11 12 13 1 2 3 4 5 6 7 8 9 10 14 15 16 17 18 19 20 # The foreground loop preempts the background one. Exit 0 # Nasimuddin Ansari suggests adding sleep 1 #+ after the echo -n '$i' in lines 6 and 14, #+ for some real fun.

Redirection from/to stdin or stdout dash. Bash$ cat - abc abc. Ctl-D As expected, cat - echoes stdin, in this case keyboarded user input, to stdout. But, does I/O redirection using - have real-world applications? (cd /source/directory && tar cf -. ) (cd /dest/directory && tar xpvf -) # Move entire file tree from one directory to another # courtesy Alan Cox, with a minor change # 1) cd /source/directory # Source directory, where the files to be moved are.

# 2) && # 'And-list': if the 'cd' operation successful, # then execute the next command. # 3) tar cf -. # The 'c' option 'tar' archiving command creates a new archive, # the 'f' (file) option, followed by '-' designates the target file # as stdout, and do it in current directory tree ('.' # 4) # Piped to.

) # a subshell # 6) cd /dest/directory # Change to the destination directory. # 7) && # 'And-list', as above # 8) tar xpvf - # Unarchive ('x'), preserve ownership and file permissions ('p'), # and send verbose messages to stdout ('v'), # reading data from stdin ('f' followed by '-'). # # Note that 'x' is a command, and 'p', 'v', 'f' are options.

# More elegant than, but equivalent to: # cd source/directory # tar cf -. (cd./dest/directory; tar xpvf -) # # Also having same effect: # cp -a /source/directory/. /dest/directory # Or: # cp -a /source/directory/. /source/directory/.^. /dest/directory # If there are hidden files in /source/directory. Bunzip2 -c linux-2.6.16.tar.bz2 tar xvf - # -uncompress tar file- -then pass it to 'tar'- # If 'tar' has not been patched to handle 'bunzip2', #+ this needs to be done in two discrete steps, using a pipe.

# The purpose of the exercise is to unarchive 'bzipped' kernel source. Note that in this context the '-' is not itself a Bash operator, but rather an option recognized by certain UNIX utilities that write to stdout, such as tar, cat, etc. Bash$ echo 'whatever' cat - whatever Where a filename is expected, - redirects output to stdout (sometimes seen with tar cf), or accepts input from stdin, rather than from a file.

This is a method of using a file-oriented utility as a filter in a pipe. Bash$ file Usage: file -bciknvzL -f namefile -m magicfiles file. By itself on the command-line, fails with an error message. Add a '-' for a more useful result.

This causes the shell to await user input. Bash$ file - abc standard input: ASCII text bash$ file - #!/bin/bash standard input: Bourne-Again shell script text executable Now the command accepts input from stdin and analyzes it. The '-' can be used to pipe stdout to other commands. This permits such stunts as. Using to compare a file with a section of another: grep Linux file1 diff file2 - Finally, a real-world example using - with.