Comparing files - Revision history

Xaizek: /* Plugging the script into vifm */ Fix expansion of file names with quotes

2014-09-15T11:25:24Z

Plugging the script into vifm: Fix expansion of file names with quotes

Xaizek: /* Comparison script */ Make comparison of directories recursive

2014-07-29T15:34:41Z

Comparison script: Make comparison of directories recursive

178.136.81.41: Use "source" tag instead of "syntaxhighlight"

2014-07-28T14:44:01Z

Use "source" tag instead of "syntaxhighlight"

178.136.81.41: /* Plugging the script into vifm */

2014-07-28T14:37:03Z

Plugging the script into vifm

Xaizek: Dashes => hyphens

2014-07-20T12:12:31Z

Dashes => hyphens

Xaizek: Initial version of comparing files script and command

2014-07-18T18:45:03Z

Initial version of comparing files script and command

New page

== Comparison script ==

The script below takes two arguments on the command-line and compares them via <code>[https://en.wikipedia.org/wiki/Diff diff]</code> command. It also echoes generic human-readable answer saying whether two file system objects are equal. As <code>diff</code> compares directories as well as files, paths to directories are valid arguments as well.

<syntaxhighlight lang="bash">
#!/bin/bash

if [ $# != 2 ] ; then
echo 'Expected exactly two arguments'
exit 1
fi

if [ -f "$1" -a -f "$2" ]; then
: # OK, do nothing here
elif [ -d "$1" -a -d "$2" ]; then
: # OK, do nothing here
else
if [ -f "$1" ]; then
type_of_1='file'
else
type_of_1='directory'
fi
if [ -f "$2" ]; then
type_of_2='file'
else
type_of_2='directory'
fi
echo "Arguments are of different type ($type_of_1/$type_of_2)"
exit 1
fi

if diff "$1" "$2" > /dev/null 2>&1; then
echo 'Equal'
else
echo 'Not equal'
fi
</syntaxhighlight>

== Plugging the script into vifm ==

To use it in vifm:

# Save the script as <code>compare-cmd</code> (not <code>[https://en.wikipedia.org/wiki/Cmp_(Unix) cmp]</code> or <code>[http://linux.die.net/man/1/compare compare]</code> to avoid name conflict with existing tools) at one of directories listed in your <code>[https://en.wikipedia.org/wiki/PATH_(variable) $PATH]</code> environment variable or under <code>$VIFM/scripts</code> (most likely that it's <code>~/.vifm/scripts</code>).
# On Unix-like operating systems make the script file executable by running<br><code>[https://en.wikipedia.org/wiki/Chmod chmod] +x compare-cmp</code>
# Add following lines to your <code>vifmrc</code>:<code>
command! cmpinternal compare-cmd %a %S
command! cmp : if expand('%c') == expand('%f')
\ | echo expand('Comparing %"c and %"C:t ...')
\ | cmpinternal %c %C
\ | else
\ | echo expand('Comparing files: %"f ...')
\ | cmpinternal %f
\ | endif
</code>

Explanation of key parts:
* <code>cmpinternal</code> - a trick to invoke external command. Calling <code>execute "!compare-cmd ... %S"</code> reparses command-line which leads to loosing results of command execution (they are overwritten by execution of <code>if-else-endif</code> block).
* <code>expand('%c') == expand('%f')</code> - check whether only one file is selected in current pane.

== Usage ==

* Run <code>:cmp</code> without selection or with single file selection to compare files under cursors in two panes.
* Run <code>:cmp</code> after selecting two files in the current pane to compare them.

Results are printed on the status bar (because of <code>%S</code> macro in <code>cmdinternal</code>).

@@ Line 45: / Line 45: @@
 # Add following lines to your <code>vifmrc</code>:<code>
      command! cmpinternal compare-cmd %a %S
-     command! cmp : if expand('%c') == expand('%f')
+     command! cmp : if expand('%%c') == expand('%%f')
-                \ |     echo expand('Comparing %"c and %"C:t ...')
+                \ |     echo expand('Comparing %%"c and %%"C:t ...')
                 \ |     cmpinternal %c %C
                 \ | else
-                \ |     echo expand('Comparing files: %"f ...')
+                \ |     echo expand('Comparing files: %%"f ...')
                 \ |     cmpinternal %f
                 \ | endif
@@ Line 56: / Line 56: @@
 Explanation of key parts:
 * <code>cmpinternal</code> — a trick to invoke external command. Calling <code>execute "!compare-cmd ... %S"</code> reparses command-line which leads to loosing results of command execution (they are overwritten by execution of <code>if-else-endif</code> block).
-* <code>expand('%c') == expand('%f')</code> — check whether only one file is selected in current pane.
+* Double percent sign in arguments for the <code>expand()</code> function (e.g. <code>expand('%%c')</code>) — macros are automatically expanded for user-defined commands, so <code>%</code> symbol should be escaped with itself for expansion to be performed by <code>expand()</code> function. It's important as otherwise unescaped quotes or other special characters in file names can break command syntax.
 == Usage ==

@@ Line 1: / Line 1: @@
 == Comparison script ==
-The script below takes two arguments on the command-line and compares them via <code>[https://en.wikipedia.org/wiki/Diff diff]</code> command. It also echoes generic human-readable answer saying whether two file system objects are equal. As <code>diff</code> compares directories as well as files, paths to directories are valid arguments as well.
+The script below takes two arguments on the command-line and compares them via <code>[https://en.wikipedia.org/wiki/Diff diff]</code> command. It also echoes generic human-readable answer saying whether two file system objects are equal. As <code>diff</code> is able to compare both directories and files, paths to directories are valid arguments as well.
 <source lang="bash">
@@ Line 12: / Line 12: @@
 if [ -f "$1" -a -f "$2" ]; then
-     : # OK, do nothing here
+     args=
 elif [ -d "$1" -a -d "$2" ]; then
-     : # OK, do nothing here
+     args='-r'
 else
      if [ -f "$1" ]; then
@@ Line 30: / Line 30: @@
 fi
-if diff "$1" "$2" > /dev/null 2>&1; then
+if diff $args "$1" "$2" > /dev/null 2>&1; then
      echo 'Equal'
 else

@@ Line 3: / Line 3: @@
 The script below takes two arguments on the command-line and compares them via <code>[https://en.wikipedia.org/wiki/Diff diff]</code> command. It also echoes generic human-readable answer saying whether two file system objects are equal. As <code>diff</code> compares directories as well as files, paths to directories are valid arguments as well.
-<syntaxhighlight lang="bash">
+<source lang="bash">
 #!/bin/bash
@@ Line 35: / Line 35: @@
      echo 'Not equal'
 fi
-</syntaxhighlight>
+</source>
 == Plugging the script into vifm ==

@@ Line 39: / Line 39: @@
 == Plugging the script into vifm ==
-To use it in vifm:
+To use it in Vifm:
 # Save the script as <code>compare-cmd</code> (not <code>[https://en.wikipedia.org/wiki/Cmp_(Unix) cmp]</code> or <code>[http://linux.die.net/man/1/compare compare]</code> to avoid name conflict with existing tools) at one of directories listed in your <code>[https://en.wikipedia.org/wiki/PATH_(variable) $PATH]</code> environment variable or under <code>$VIFM/scripts</code> (most likely that it's <code>~/.vifm/scripts</code>).