diff options
| author |   Mark Loeser <halcy0n@gentoo.org> | 2006-05-17 07:18:54 +0000 |
|---|---|---|
| committer | Mark Loeser <halcy0n@gentoo.org> | 2006-05-17 07:18:54 +0000 |
| commit | 5ff6a780ae4a8d0308204058cc88917cdd763854 (patch) | |
| tree | 684827bc9d4925a40055d0629a73b52c46e1c1e5 | |
| parent | gtk2 -> gtk (diff) | |
| download | devmanual-5ff6a780ae4a8d0308204058cc88917cdd763854.tar.gz devmanual-5ff6a780ae4a8d0308204058cc88917cdd763854.tar.bz2 devmanual-5ff6a780ae4a8d0308204058cc88917cdd763854.zip | |
Add the remaining tools-references that were missing
git-svn-id: svn+ssh://svn.gentoo.org/var/svnroot/devmanual/trunk@42 176d3534-300d-0410-8db8-84e73ed771c3
| -rw-r--r-- | tools-reference/sed/text.xml | 904 | ||||
| -rw-r--r-- | tools-reference/sort/text.xml | 27 | ||||
| -rw-r--r-- | tools-reference/text.xml | 2 | ||||
| -rw-r--r-- | tools-reference/tr/text.xml | 62 | ||||
| -rw-r--r-- | tools-reference/uniq/text.xml | 24 |
5 files changed, 1019 insertions, 0 deletions
diff --git a/tools-reference/sed/text.xml b/tools-reference/sed/text.xml new file mode 100644 index 0000000..c07254d --- /dev/null +++ b/tools-reference/sed/text.xml @@ -0,0 +1,904 @@ +<?xml version="1.0"?> +<guide self="tools-reference/sed/"> +<chapter> +<title>sed -- Stream Editor</title> +<body> + +<p> +Sometimes it is better to use regular expressions to manipulate content rather +than patching sources. This can be used for small changes, especially those +which are likely to create patch conflicts across versions. The canonical way of +doing this is via <c>sed</c>: +</p> + +<codesample lang="ebuild"> +# This plugin is mapped to the 'h' key by default, which conflicts with some +# other mappings. Change it to use 'H' instead. +sed -i 's/\(noremap <buffer> \)h/\1H/' info.vim \ + || die 'sed failed' +</codesample> + +<p> +Another common example is appending a <c>-gentoo-blah</c> version string (some +upstreams like us to do this so that they can tell exactly which package they're +dealing with). Again, we can use <c>sed</c>. Note that the <c>${PR}</c> variable will +be set to <c>r0</c> if we don't have a <c>-r</c> component in our version. +</p> + +<codesample lang="ebuild"> +# Add in the Gentoo -r number to fluxbox -version output. We need to look +# for the line in version.h.in which contains "__fluxbox_version" and append +# our content to it. +if [[ "${PR}" == "r0" ]] ; then + suffix="gentoo" +else + suffix="gentoo-${PR}" +fi +sed -i \ + -e "s~\(__fluxbox_version .@VERSION@\)~\1-${suffix}~" \ + version.h.in || die "version sed failed" +</codesample> + +<p> +It is also possible to extract content from existing files to create new files +this way. Many <c>app-vim</c> ebuilds use this technique to extract documentation +from the plugin files and convert it to Vim help format. +</p> + +<codesample lang="ebuild"> +# This plugin uses an 'automatic HelpExtractor' variant. This causes +# problems for us during the unmerge. Fortunately, sed can fix this +# for us. First, we extract the documentation: +sed -e '1,/^" HelpExtractorDoc:$/d' \ + ${S}/plugin/ZoomWin.vim > ${S}/doc/ZoomWin.txt \ + || die "help extraction failed" +# Then we remove the help extraction code from the plugin file: +sed -i -e '/^" HelpExtractor:$/,$d' ${S}/plugin/ZoomWin.vim \ + || die "help extract remove failed" +</codesample> + +<p> +A summary of the more common ways of using <c>sed</c> and a description of +commonly used address and token patterns follows. Note that some of these +constructs are specific to <c>GNU sed 4</c> <d/> on non-GNU userland archs, the +<c>sed</c> command must be aliased to GNU sed. Also note that <c>GNU sed 4</c> is +guaranteed to be installed as part of <c>system</c>. This was not always the case, +which is why some packages, particularly those which use <c>sed -i</c>, have +<c>DEPEND</c> s upon <c>>=sys-apps/sed-4</c>. +</p> + +<section> +<title>Basic <c>sed</c> Invocation</title> +<body> + +<p> +The basic form of a call is: +</p> + +<codesample lang="ebuild"> +sed [ option flags ] \ + -e 'first command' \ + -e 'second command' \ + -e 'and so on' \ + input-file > output-file \ + || die "Oops, sed didn't work!" +</codesample> + +<p> +For cases where the input and output files are the same, the inplace option +should be used. This is done by passing <c>-i</c> as one of the option flags. +</p> + +<p> +Usually <c>sed</c> prints out every line of the created content. To obtain only +explicitly printed lines, the <c>-n</c> flag should be used. +</p> + +<note> +The term <e>pattern</e> refers to the description of text being matched. +</note> + +</body> +</section> + +<section> +<title>Simple Text Substitution using <c>sed</c></title> +<body> + +<p> +The most common form of <c>sed</c> is to replace all instances of <c>"some text"</c> +with <c>"different content"</c>. This is done as follows: +</p> + +<codesample lang="ebuild"> +# replace all instances of "some text" with "different content" in +# somefile.txt +sed -i -e 's/some text/different content/g' somefile.txt || \ + die "Sed broke!" +</codesample> + +<note> +The <c>/g</c> flag is required to replace <e>all</e> occurrences. Without this +flag, only the first match on each line is replaced. +</note> + +<warning> +The above will replace <c>"irksome texting"</c> with +<c>"irkdifferent contenting"</c>, which may not be desired. +</warning> + +<p> +If the pattern or the replacement string contains the forward slash character, +it is usually easiest to use a different delimiter. Most punctuation characters +are allowed, although backslash and any form of brackets should be avoided. +</p> + +<codesample lang="ebuild"> +# replace all instances of "/usr/local" with "/usr" +sed -i -e 's~/usr/local~/usr~g' somefile.txt || \ + die "sed broke" +</codesample> + +<p> +Patterns can be made to match only at the start or end of a line by using the +<c>^</c> and <c>$</c> metacharacters. A <c>^</c> means "match at the start of a line +only", and <c>$</c> means "match at the end of a line only". By using both in a +single statement, it is possible to match exact lines. +</p> + +<codesample lang="ebuild"> +# Replace any "hello"s which occur at the start of a line with "howdy". +sed -i -e 's!^hello!howdy!' data.in || die "sed failed" +</codesample> + +<note> +There is no need for a <c>!g</c> suffix here. +</note> + +<codesample lang="ebuild"> +# Replace any "bye"s which occur at the end of a line with "cheerio!". +sed -i -e 's,bye$,cheerio!,' data.in || die "sed failed" +</codesample> + +<codesample lang="ebuild"> +# Replace any lines which are exactly "change this line" with "have a +# cookie". +sed -i -e 's-^change this line$-have a cookie-' data.in || die "Oops" +</codesample> + +<p> +To ignore case in the pattern, add the <c>/i</c> flag. +</p> + +<codesample lang="ebuild"> +# Replace any "emacs" instances (ignoring case) with "Vim" +sed -i -e 's/emacs/Vim/gi' editors.txt || die "Ouch" +</codesample> + +<warning> +Case insensitive matching doesn't work correctly when backreferences +are used. +</warning> + +</body> +</section> + +<section> +<title>Regular Expression Substitution using <c>sed</c></title> +<body> + +<p> +It is also possible to do more complex matches with <c>sed</c>. Some examples could +be: +</p> + +<ul> + <li> + Match any three digits + </li> + <li> + Match either "foo" or "bar" + </li> + <li> + Match any of the letters "a", "e", "i", "o" or "u" + </li> +</ul> + +<p> +These types of pattern can be chained together, leading to things like "match +any vowel followed by two digits followed by either foo or bar". +</p> + +<p> +To match any of a set of characters, a <e>character class</e> can be used. These come +in three forms. +</p> + +<ul> + <li> + A backslash followed by a letter. <c>\d</c>, for example, matches a single digit + (any of 0, 1, 2, ... 9). <c>\s</c> matches a single whitespace character. A table + of the more useful classes is provided later in this document. + </li> + <li> + A group of characters inside square brackets. <c>[aeiou]</c>, for example, + matches any one of 'a', 'e', 'i', 'o' or 'u'. Ranges are allowed, such as + <c>[0-9A-Fa-fxX]</c>, which could be used to match any hexadecimal digit or the + characters 'x' and 'X'. Inverted character classes, such as <c>[^aeiou]</c>, + match any single character <e>except</e> those listed. + </li> + <li> + A POSIX character class is a special named group of characters that are + locale-aware. For example, <c>[[:alpha:]]</c> matches any 'alphabet' character in + the current locale. A table of the more useful classes is provided later in + this document. + </li> +</ul> + +<note> +The regex <c>a[^b]</c> does <b>not</b> mean "match a, so long as it does not +have a 'b' after it". It means "match a followed by exactly one character which +is not a 'b'". This is important when one considers a line ending in the +character 'a'. +</note> + +<note> +At the time of writing, the <c>sed</c> documentation (<c>man sed</c> and +<c>sed.info</c>) does not mention that POSIX character classes are supported. +Consult <uri +link="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap09.html#tag_09_03"> +IEEE1003.1-2004-9.3</uri> for full details of how these <e>should</e> work, and +the <c>sed</c> source code for full details of how these <e>actually</e> work. +</note> + +<p> +To match any one of multiple options, <e>alternation</e> can be used. The basic form +is <c>first\|second\|third</c>. +</p> + +<p> +To group items to avoid ambiguity, the <c>\(parentheses\)</c> construct may be +used. To match "iniquity" or "infinity", one could use <c>in\(iqui\|fini\)ty</c>. +</p> + +<p> +To optionally match an item, add a <c>\?</c> after it. For example, <c>colou\?r</c> +matches both "colour" and "color". This can also be applied to character classes +and groups in parentheses, for example <c>\(in\)\?finite\(ly\)\?</c>. Further atoms +are available for matching "one or more", "zero or more", "at least n", "between +n and m" and so on <d/> these are summarised later in this document. +</p> + +<p> +There are also some special constructs which can be used in the replacement part +of a substitution command. To insert the contents of the pattern's first matched +bracket group, use <c>\1</c>, for the second use <c>\2</c> and so on up to <c>\9</c>. An +unescaped ampersand <c>&</c> character can be used to insert the entire contents of +the match. These and other replace atoms are summarised later in this document. +</p> + +</body> +</section> + +<section> +<title>Addresses in <c>sed</c></title> +<body> + +<p> +Many <c>sed</c> commands can be applied only to a certain line or range of lines. +This could be useful if one wishes to operate only on the first ten lines of a +document, for example. +</p> + +<p> +The simplest form of address is a single positive integer. This will cause the +following command to be applied only to the line in question. Line numbering +starts from 1, but the address 0 can be useful when one wishes to insert text +<e>before</e> the first line. If the address 100 is used on a 50 line document, the +associated command will never be executed. +</p> + +<p> +To match the last line in a document, the <c>$</c> address may be used. +</p> + +<p> +To match any lines that match a given regular expression, the form +<c>/pattern/</c> is allowed. This can be useful for finding a particular line and +then making certain changes to it <d/> sometimes it is simpler to handle this in +two stages rather than using one big scary <c>s///</c> command. When used in +ranges, it can be useful for finding all text between two given markers or +between a given marker and the end of the document. +</p> + +<p> +To match a range of addresses, <c>addr1,addr2</c> can be used. Most address +constructs are allowed for both the start and the end addresses. +</p> + +<p> +Addresses may be inverted with an exclamation mark. To match all lines <e>except</e> +the last, <c>$!</c> may be used. +</p> + +<p> +Finally, if no address is given for a command, the command is applied to every +line in the input. +</p> + +<note> +GNU <c>sed</c> does <b>not</b> support the <c>%</c> address forms found in some +other implementations. It also doesn't support <c>/addr/+offset</c>, that's an +<c>ex</c> thing... +</note> + +<p> +Other more complex options involving chaining addresses are available. These are +not discussed in this document. +</p> + +</body> +</section> + +<section> +<title>Content Deletion using <c>sed</c></title> +<body> + +<p> +Lines may be deleted from a file using <c>address d</c> command. To delete the +third line of a file, one could use <c>3d</c>, and to filter out all lines +containing "fred", <c>/fred/d</c>. +</p> + +<note> +sed -e <c>/fred/d</c> is <e>not</e> the same as <c>s/.<e>fred.</e>//</c> <d/> the former +will delete the lines including the newline, whereas the latter will delete the +lines' contents but not the newline. +</note> + +</body> +</section> + +<section> +<title>Content Extraction using <c>sed</c></title> +<body> + +<p> +When the <c>-n</c> option is passed to <c>sed</c>, no output is printed by default. +The <c>p</c> command can be used to display content. For example, to print lines +containing "infra monkey", the command <c>sed -n -e '/infra monkey/p'</c> could be +used. Ranges may also be printed <d/> <c>sed -n -e '/^START$/,/^END$/p'</c> is +sometimes useful. +</p> + +</body> +</section> + +<section> +<title>Inserting Content using <c>sed</c></title> +<body> + +<p> +To insert text with sed use a <c>address a</c> or <c>i</c> command. The +<c>a</c> command inserts on the line following the match while the <c>i</c> +command inserts on the line before the match. +</p> + +<p> +As usual, an address can be either a line number or a regular +expression: a line number command will only be executed once and a +regular expression insert/append will be executed for each match. +</p> + +<codesample lang="ebuild"> +# Add 'Bob' after the 'To:' line: +sed -i -e '/^To: $/a Bob' data.in || die "Oops" + +# Add 'From: Alice' before the 'To:' line: +sed -i -e '/^To: $/i From: Alice' + +# Note that the spacing between the 'i' or 'a' and 'Bob' or 'From: Alice' is simply ignored' + +# Add 'From: Alice' indented by two spaces: (You only need to escape the first space) +sed -i -e '/^To: $/i\ From: Alice' +</codesample> + +<p> +Note that you should use a match instead of a line number wherever +possible. This reduces problems if a line is added at the beginning of +the file, for example, causing your sed script to break. +</p> + +</body> +</section> + +<section> +<title>Regular Expression Atoms in <c>sed</c></title> +<body> + +<subsection> +<title>Basic Atoms</title> +<body> + +<table> + <tr> + <th> + Atom + </th> + <th> + Purpose + </th> + </tr> + <tr> + <ti> + <c>text</c> + </ti> + <ti> + Literal text + </ti> + </tr> + <tr> + <ti> + <c>\( \)</c> + </ti> + <ti> + Grouping + </ti> + </tr> + <tr> + <ti> + <c>\|</c> + </ti> + <ti> + Alternation, a <e>or</e> b + </ti> + </tr> + <tr> + <ti> + <c>*</c> <c>\?</c> <c>\+</c> <c>\{\}</c> + </ti> + <ti> + Repeats, see below + </ti> + </tr> + <tr> + <ti> + <c>.</c> + </ti> + <ti> + Any single character + </ti> + </tr> + <tr> + <ti> + <c>^</c> + </ti> + <ti> + Start of line + </ti> + </tr> + <tr> + <ti> + <c>$</c> + </ti> + <ti> + End of line + </ti> + </tr> + <tr> + <ti> + <c>[abc0-9]</c> + </ti> + <ti> + Any one of + </ti> + </tr> + <tr> + <ti> + <c>[^abc0-9]</c> + </ti> + <ti> + Any one character except + </ti> + </tr> + <tr> + <ti> + <c>[[:alpha:]]</c> + </ti> + <ti> + POSIX character class, see below + </ti> + </tr> + <tr> + <ti> + <c>\1</c> .. <c>\9</c> + </ti> + <ti> + Backreference + </ti> + </tr> + <tr> + <ti> + <c>\x</c> (any special character) + </ti> + <ti> + Match character literally + </ti> + </tr> + <tr> + <ti> + <c>\x</c> (normal characters) + </ti> + <ti> + Shortcut, see below + </ti> + </tr> +</table> + +</body> +</subsection> + +<subsection> +<title>Character Class Shortcuts</title> +<body> + +<table> + <tr> + <th> + Atom + </th> + <th> + Description + </th> + </tr> + <tr> + <ti> + <c>\a</c> + </ti> + <ti> + "BEL" character + </ti> + </tr> + <tr> + <ti> + <c>\f</c> + </ti> + <ti> + "Form Feed" character + </ti> + </tr> + <tr> + <ti> + <c>\t</c> + </ti> + <ti> + "Tab" character + </ti> + </tr> + <tr> + <ti> + <c>\w</c> + </ti> + <ti> + "Word" (a letter, digit or underscore) character + </ti> + </tr> + <tr> + <ti> + <c>\W</c> + </ti> + <ti> + "Non-word" character + </ti> + </tr> +</table> + +</body> +</subsection> + +<subsection> +<title>POSIX Character Classes</title> +<body> + +<p> +Read the source, it's the only place these're documented properly... +</p> + +<table> + <tr> + <th> + Class + </th> + <th> + Description + </th> + </tr> + <tr> + <ti> + <c>[[:alpha:]]</c> + </ti> + <ti> + Alphabetic characters + </ti> + </tr> + <tr> + <ti> + <c>[[:upper:]]</c> + </ti> + <ti> + Uppercase alphabetics + </ti> + </tr> + <tr> + <ti> + <c>[[:lower:]]</c> + </ti> + <ti> + Lowercase alphabetics + </ti> + </tr> + <tr> + <ti> + <c>[[:digit:]]</c> + </ti> + <ti> + Digits + </ti> + </tr> + <tr> + <ti> + <c>[[:alnum:]]</c> + </ti> + <ti> + Alphabetic and numeric characters + </ti> + </tr> + <tr> + <ti> + <c>[[:xdigit:]]</c> + </ti> + <ti> + Digits allowed in a hexadecimal number + </ti> + </tr> + <tr> + <ti> + <c>[[:space:]]</c> + </ti> + <ti> + Whitespace characters + </ti> + </tr> + <tr> + <ti> + <c>[[:print:]]</c> + </ti> + <ti> + Printable characters + </ti> + </tr> + <tr> + <ti> + <c>[[:punct:]]</c> + </ti> + <ti> + Punctuation characters + </ti> + </tr> + <tr> + <ti> + <c>[[:graph:]]</c> + </ti> + <ti> + Non-blank characters + </ti> + </tr> + <tr> + <ti> + <c>[[:cntrl:]]</c> + </ti> + <ti> + Control characters + </ti> + </tr> +</table> + +</body> +</subsection> + +<subsection> +<title>Count Specifiers</title> +<body> + +<table> + <tr> + <th> + Atom + </th> + <th> + Description + </th> + </tr> + <tr> + <ti> + <c>*</c> + </ti> + <ti> + Zero or more (greedy) + </ti> + </tr> + <tr> + <ti> + <c>\+</c> + </ti> + <ti> + One or more (greedy) + </ti> + </tr> + <tr> + <ti> + <c>\?</c> + </ti> + <ti> + Zero or one (greedy) + </ti> + </tr> + <tr> + <ti> + <c>\{N\}</c> + </ti> + <ti> + Exactly N + </ti> + </tr> + <tr> + <ti> + <c>\{N,M\}</c> + </ti> + <ti> + At least N and no more than M (greedy) + </ti> + </tr> + <tr> + <ti> + <c>\{N,\}</c> + </ti> + <ti> + At least N (greedy) + </ti> + </tr> +</table> + +</body> +</subsection> + +</body> +</section> + +<section> +<title>Replacement Atoms in <c>sed</c></title> +<body> + +<table> + <tr> + <th> + Atom + </th> + <th> + Description + </th> + </tr> + <tr> + <ti> + <c>\1</c> .. <c>\9</c> + </ti> + <ti> + Captured <c>\( \)</c> contents + </ti> + </tr> + <tr> + <ti> + <c>&</c> + </ti> + <ti> + The entire matched text + </ti> + </tr> + <tr> + <ti> + <c>\L</c> + </ti> + <ti> + All subsequent characters are converted to lowercase + </ti> + </tr> + <tr> + <ti> + <c>\l</c> + </ti> + <ti> + The following character is converted to lowercase + </ti> + </tr> + <tr> + <ti> + <c>\U</c> + </ti> + <ti> + All subsequent characters are converted to uppercase + </ti> + </tr> + <tr> + <ti> + <c>\u</c> + </ti> + <ti> + The following character is converted to uppercase + </ti> + </tr> + <tr> + <ti> + <c>\E</c> + </ti> + <ti> + Cancel the most recent <c>\L</c> or <c>\U</c> + </ti> + </tr> +</table> + +</body> +</section> + +<section> +<title>Details of <c>sed</c> Match Mechanics</title> +<body> + +<p> +GNU <c>sed</c> uses a traditional (non-POSIX) nondeterministic finite automaton with +extensions to support capturing to do its matching. This means that in all +cases, the match with the leftmost starting position will be favoured. Of all +the leftmost possible matches, favour will be given to leftmost alternation +options. Finally, all other things being equal favour will be given to the +longest of the leftmost counting options. +</p> + +<p> +Most of this is in violation of one of the sillier POSIX rules, so it's best not +to rely upon it. It <e>is</e> safe to assume that <c>sed</c> will always pick the leftmost +match, and that it will match greedily with priority given to items earlier in +the pattern. +</p> + +</body> +</section> + +<section> +<title>Notes on Performance with <c>sed</c></title> +<body> + +<todo> +write this +</todo> + +</body> +</section> + +<section> +<title>Recommended Further Reading for Regular Expressions</title> +<body> + +<p> +The author recommends <e>Mastering Regular Expressions</e> by Jeffrey E. F. Friedl +for those who wish to learn more about regexes. This text is remarkably devoid +of phrases like "let <c>t</c> be a finite contiguous sequence such that <c>t[n] ∈ ∑ +∀ n</c>", and was <e>not</e> written by someone whose pay cheque depended upon them being +able to express simple concepts with pages upon pages of mathematical and Greek +symbols. +</p> + +</body> +</section> + +</body> +</chapter> +</guide> diff --git a/tools-reference/sort/text.xml b/tools-reference/sort/text.xml new file mode 100644 index 0000000..ebbc69c --- /dev/null +++ b/tools-reference/sort/text.xml @@ -0,0 +1,27 @@ +<?xml version="1.0"?> +<guide self="tools-reference/sort/"> +<chapter> +<title>sort -- Sorting Text</title> +<body> + +<p> +The <c>sort</c> tool can be used to sort text. It sorts the contents of the files +named on the commandline, or the text provided on standard input if no files are +given. Output is to standard output by default, unless a <c>-o filename</c> option +is provided. +</p> + +<p> +To ignore case, the <c>-f</c> switch may be used. +</p> + +<p> +Many other options are available. See <c>man sort</c> and <uri +link="http://www.opengroup.org/onlinepubs/000095399/utilities/sort.html"> +IEEE1003.1-2004-sort</uri> for details. +</p> + +</body> +</chapter> +</guide> + diff --git a/tools-reference/text.xml b/tools-reference/text.xml index 98cf889..4239adb 100644 --- a/tools-reference/text.xml +++ b/tools-reference/text.xml @@ -33,10 +33,12 @@ ebuilds. <include href="head-and-tail/"/> <!-- <include href="repoman/"/> +--> <include href="sed/"/> <include href="sort/"/> <include href="tr/"/> <include href="uniq/"/> +<!-- <include href="xargs/"/>--> </guide> diff --git a/tools-reference/tr/text.xml b/tools-reference/tr/text.xml new file mode 100644 index 0000000..e7002e1 --- /dev/null +++ b/tools-reference/tr/text.xml @@ -0,0 +1,62 @@ +<?xml version="1.0"?> +<guide self="tools-reference/tr/"> +<chapter> +<title>tr -- Character Translation</title> +<body> + +<p> +The <c>tr</c> command can be used to translate, squeeze and delete character +sequences. See <c>man tr</c> and <uri +link="http://www.opengroup.org/onlinepubs/000095399/utilities/tr.html"> +IEEE1003.1-2004-tr</uri> for the full specification. +</p> + +<note> +<c>tr</c>, unlike most other utilities, only reads from standard input +and only writes to standard output. Therefore, you will have to use +<c>tr [options] < input > output</c>. +</note> + +<p> +<c>tr</c> operates in a number of modes, depending upon the invocation: +</p> + +<dl> + <dt> + Deleting characters + </dt> + <dd> + <p> + To delete all occurrences of certain characters, use <c>tr -d asdf</c>. + </p> + </dd> + <dt> + Deleting repeated characters + </dt> + <dd> + <p> + To replace repeated characters with a single character ('squeeze'), use + <c>tr -s asdf</c>. + </p> + </dd> + <dt> + Transliterating characters + </dt> + <dd> + <p> + To replace all 'a' characters with '1', all 'b' with '2' and all 'c' with + '3', use <c>tr abc 123</c>. + </p> + </dd> +</dl> + +<p> +Certain special forms are allowed for the arguments. <c>a-z</c> expands to all +characters from 'a' to 'z', <c>\t</c> represents a tab and so on. See the +documentation for a full list. +</p> + +</body> +</chapter> +</guide> + diff --git a/tools-reference/uniq/text.xml b/tools-reference/uniq/text.xml new file mode 100644 index 0000000..409fa44 --- /dev/null +++ b/tools-reference/uniq/text.xml @@ -0,0 +1,24 @@ +<?xml version="1.0"?> +<guide self="tools-reference/uniq/"> +<chapter> +<title>uniq -- Filtering Duplicates</title> +<body> + +<p> +The <c>uniq</c> utility can be used to filter <b>adjacent</b> duplicate lines in files +or in the text provided through standard input. +</p> + +<note> +Instead of using <c>sort | uniq</c>, one should use <c>sort -u</c>. +</note> + +<p> +See <c>man uniq</c> and <uri +link="http://www.opengroup.org/onlinepubs/000095399/utilities/uniq"> +IEEE1003.1-2004-uniq</uri> for details. +</p> + +</body> +</chapter> +</guide> |