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authorPádraig Brady <P@draigBrady.com>2015-11-25 11:57:34 +0000
committerPádraig Brady <P@draigBrady.com>2015-11-25 15:12:35 +0000
commitbc1bf0fdc256e6243c1df067654b87d507adb84e (patch)
treef74eeb7dd987408b3d008f88b46702d56ea3cfe5 /doc
parent5595024a2fdd726d88d57c5a06b633b752ef31db (diff)
downloadcoreutils-bc1bf0fdc256e6243c1df067654b87d507adb84e.tar.xz
doc: clarify descriptions for tr --squeeze-repeats
* doc/coreutils.texi (uniq invocation): Fix the description of problematic input to say "blank lines" rather than "two or more blank lines". (tr invocation): Clarify that -s only works with SET1 when not translating (when SET2 not specified). Also explicitly state in examples where blank lines are deleted. Also add "deleting" to the menu item. * src/tr.c (usage): Improve the -s summary to say it always operates on the last specified SET.
Diffstat (limited to 'doc')
-rw-r--r--doc/coreutils.texi30
1 files changed, 17 insertions, 13 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 88e16503d..9a27cb109 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -297,7 +297,7 @@ Operating on characters
* Character sets:: Specifying sets of characters
* Translating:: Changing one set of characters to another
-* Squeezing:: Squeezing repeats and deleting
+* Squeezing and deleting:: Removing characters
Directory listing
@@ -1609,7 +1609,8 @@ if @option{-b} is in effect.
@opindex -s
@opindex --squeeze-blank
@cindex squeezing empty lines
-Suppress repeated adjacent empty lines; output just one empty line
+@cindex squeezing blank lines
+Suppress repeated adjacent blank lines; output just one empty line
instead of several.
@item -t
@@ -4968,9 +4969,9 @@ may be better suited for output direct to users.
@macro ambiguousGroupNote
Note that when groups are delimited and the input stream contains
-two or more consecutive blank lines, then the output is ambiguous.
-To avoid that, filter the input through @samp{tr -s '\\n'} to replace
-each sequence of consecutive newlines with a single newline.
+blank lines, then the output is ambiguous.
+To avoid that, filter the input through @samp{tr -s '\\n'} to
+remove blank lines.
@end macro
@ambiguousGroupNote
@@ -6215,7 +6216,7 @@ options. @xref{Common options}. Options must precede operands.
@menu
* Character sets:: Specifying sets of characters.
* Translating:: Changing one set of characters to another.
-* Squeezing:: Squeezing repeats and deleting.
+* Squeezing and deleting:: Removing characters.
@end menu
@@ -6438,18 +6439,20 @@ tr -cs '[:alnum:]' '[\n*]'
@end example
-@node Squeezing
+@node Squeezing and deleting
@subsection Squeezing repeats and deleting
@cindex squeezing repeat characters
@cindex deleting characters
+@cindex removing characters
When given just the @option{--delete} (@option{-d}) option, @command{tr}
removes any input characters that are in @var{set1}.
-When given just the @option{--squeeze-repeats} (@option{-s}) option,
-@command{tr} replaces each input sequence of a repeated character that
-is in @var{set1} with a single occurrence of that character.
+When given just the @option{--squeeze-repeats} (@option{-s}) option
+and not translating, @command{tr} replaces each input sequence of a
+repeated character that is in @var{set1} with a single occurrence of
+that character.
When given both @option{--delete} and @option{--squeeze-repeats}, @command{tr}
first performs any deletions using @var{set1}, then squeezes repeats
@@ -6480,7 +6483,8 @@ tr -cs '[:alnum:]' '[\n*]'
@end example
@item
-Convert each sequence of repeated newlines to a single newline:
+Convert each sequence of repeated newlines to a single newline.
+I.e., delete blank lines:
@example
tr -s '\n'
@@ -17831,8 +17835,8 @@ $ tr '[:upper:]' '[:lower:]' < whats.gnu | tr -cd '[:alnum:]_ \n' |
@end smallexample
This command turns blanks into newlines. The @option{-s} option squeezes
-multiple newline characters in the output into just one. This helps us
-avoid blank lines. (The @samp{>} is the shell's ``secondary prompt.''
+multiple newline characters in the output into just one, removing
+blank lines. (The @samp{>} is the shell's ``secondary prompt.''
This is what the shell prints when it notices you haven't finished
typing in all of a command.)