Linux bzcmp, bzdiff, bzmore, bzless, and bzgrep Commands Explained with Examples

While the bzip2 command line utility can be used to compress files, there are many other tools that let you perform basic tasks - like comparing such files - without the need to uncompress them. Here, in this tutorial, we will discuss the basics of bzcmp, bzdiff, bzmore, bzless, and bzgrep commands using some easy to understand examples.

But before we do that, it's worth mentioning that all examples in this article have been tested on an Ubuntu 18.04 LTS machine.

Linux bzcmp, bzdiff, bzmore, bzless, and bzgrep commands

We'll discuss each of these commands using Q&A-style of presentation.

Q1. How bzcmp and bzdiff commands work?

As their names suggest, these commands are used for comparing .bz2 files. Following is their syntax:

bzcmp [ cmp_options ] file1 [ file2 ]
bzdiff [ diff_options ] file1 [ file2 ]

And here's what the man page says about them:

       Bzcmp  and  bzdiff  are  used  to invoke the cmp or the diff program on
       bzip2 compressed files.  All options specified are passed  directly  to
       cmp  or diff.  If only 1 file is specified, then the files compared are
       file1 and an uncompressed file1.bz2.  If two files are specified,  then
       they  are  uncompressed  if necessary and fed to cmp or diff.  The exit
       status from cmp or diff is preserved.

Here's a basic example of bzcmp and bzdiff:

bzcmp file1.bz2 file2.bz2
bzdiff file1.bz2 file2.bz2

And the following screenshot shows the output produced by these commands:

How bzcmp and bzdiff commands work

While these commands do not explicitly offer any command line options, you can use the options from cmp and diff commands (as these tools are internally invoked by bzcmp and bzdiff commands).

Q2. How bzmore and bzless commands work?

Just like more and less, both bzmore and bzless are filters for CRT viewing, but for compressed bz2 files. To give you an even better idea, here's an excerpt about bzmore from its man page:

       Bzmore is a filter which allows examination of compressed or plain text
       files one screenful at a time on a soft-copy terminal.  bzmore works on
       files  compressed with bzip2 and also on uncompressed files.  If a file
       does not exist, bzmore looks for a file of the same name with the addi?
       tion of a .bz2 suffix.

       Bzmore  normally  pauses after each screenful, printing --More-- at the
       bottom of the screen.  If the user then types a  carriage  return,  one
       more line is displayed.  If the user hits a space, another screenful is
       displayed.  Other possibilities are enumerated later.

Of course, you can also use these commands to simply view a compressed file. Here's an example:

How bzmore and bzless commands work

Q3. How bzgrep command works?

As you'd have guessed by now, bzgrep also works on the lines of other bz series commands we've explained here. Specifically, it's grep, but for compressed files. Following is an excerpt from the man page of this command:

       Bzgrep is used to  invoke  the  grep  on  bzip2-compressed  files.  All
       options  specified  are  passed directly to grep.  If no file is speci?
       fied, then the standard input is decompressed if necessary and  fed  to
       grep.   Otherwise the given files are uncompressed if necessary and fed
       to grep.

Here's an example usage of bzgrep:

bzgrep "menu" file1.bz2

The following screenshot shows the output:

How bzgrep command works


So if you are dealing with compressed files (.bz2), and want to perform basic operations like searching, comparing, and more, you can use these commands. We've discussed the basics here. For more information about these tools, head to their man pages (here, here, and here).

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