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Dict </a> </li> <li class=md-tabs__item> <a href=../../howto/calculate-dc/ class=md-tabs__link> Howto </a> </li> <li class=md-tabs__item> <a href=../../internals/shell_options/ class=md-tabs__link> Internals </a> </li> <li class=md-tabs__item> <a href=../../misc/bashphorisms/ class=md-tabs__link> Misc </a> </li> <li class=md-tabs__item> <a href=../../scripting/bashbehaviour/ class=md-tabs__link> Scripting </a> </li> <li class=md-tabs__item> <a href=../../snipplets/ class=md-tabs__link> Snipplets </a> </li> <li class="md-tabs__item md-tabs__item--active"> <a href=../arith_expr/ class=md-tabs__link> Syntax </a> </li> <li class=md-tabs__item> <a href=../../tags/ class=md-tabs__link> Tags </a> </li> </ul> </div> </nav> <main class=md-main data-md-component=main> <div class="md-main__inner md-grid"> <div class="md-sidebar md-sidebar--primary" data-md-component=sidebar data-md-type=navigation> <div class=md-sidebar__scrollwrap> <div class=md-sidebar__inner> <nav class="md-nav md-nav--primary 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2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7m32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1m-11.4-14.7c-1.6 1-1.6 3.6 0 5.9s4.3 3.3 5.6 2.3c1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2"/></svg> </div> <div class=md-source__repository> flokoe/bash-hackers-wiki </div> </a> </div> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../.. class=md-nav__link> <span class=md-ellipsis> Start </span> </a> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_2> <label class=md-nav__link for=__nav_2 id=__nav_2_label tabindex=0> <span class=md-ellipsis> Commands </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_2_label aria-expanded=false> <label class=md-nav__title for=__nav_2> <span class="md-nav__icon md-icon"></span> Commands </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../commands/classictest/ class=md-nav__link> <span class=md-ellipsis> The classic test command </span> </a> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_2_2> <label class=md-nav__link for=__nav_2_2 id=__nav_2_2_label tabindex=0> <span class=md-ellipsis> Builtin </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=2 aria-labelledby=__nav_2_2_label aria-expanded=false> <label class=md-nav__title for=__nav_2_2> <span class="md-nav__icon md-icon"></span> Builtin </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../commands/builtin/caller/ class=md-nav__link> <span class=md-ellipsis> The caller builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/cd/ class=md-nav__link> <span class=md-ellipsis> The cd builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/declare/ class=md-nav__link> <span class=md-ellipsis> The declare builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/echo/ class=md-nav__link> <span class=md-ellipsis> The echo builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/eval/ class=md-nav__link> <span class=md-ellipsis> The eval builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/exec/ class=md-nav__link> <span class=md-ellipsis> The exec builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/exit/ class=md-nav__link> <span class=md-ellipsis> The exit builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/export/ class=md-nav__link> <span class=md-ellipsis> The export builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/kill/ class=md-nav__link> <span class=md-ellipsis> The kill builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/let/ class=md-nav__link> <span class=md-ellipsis> The let builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/local/ class=md-nav__link> <span class=md-ellipsis> The local builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/mapfile/ class=md-nav__link> <span class=md-ellipsis> The mapfile builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/printf/ class=md-nav__link> <span class=md-ellipsis> The printf command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/read/ class=md-nav__link> <span class=md-ellipsis> The read builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/readonly/ class=md-nav__link> <span class=md-ellipsis> The readonly builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/return/ class=md-nav__link> <span class=md-ellipsis> The return builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/set/ class=md-nav__link> <span class=md-ellipsis> The set builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/shift/ class=md-nav__link> <span class=md-ellipsis> The shift builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/shopt/ class=md-nav__link> <span class=md-ellipsis> The shopt builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/trap/ class=md-nav__link> <span class=md-ellipsis> The trap builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/unset/ class=md-nav__link> <span class=md-ellipsis> The unset builtin command </span> </a> </li> <li class=md-nav__item> <a href=../../commands/builtin/wait/ class=md-nav__link> <span class=md-ellipsis> The wait builtin command </span> </a> </li> </ul> </nav> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_3> <label class=md-nav__link for=__nav_3 id=__nav_3_label tabindex=0> <span class=md-ellipsis> Dict </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_3_label aria-expanded=false> <label class=md-nav__title for=__nav_3> <span class="md-nav__icon md-icon"></span> Dict </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../dict/directory/ class=md-nav__link> <span class=md-ellipsis> Directory </span> </a> </li> <li class=md-nav__item> <a href=../../dict/end_of_options/ class=md-nav__link> <span class=md-ellipsis> End of Options </span> </a> </li> <li class=md-nav__item> <a href=../../dict/exit_status/ class=md-nav__link> <span class=md-ellipsis> Exit Status </span> </a> </li> <li class=md-nav__item> <a href=../../dict/file/ class=md-nav__link> <span class=md-ellipsis> File </span> </a> </li> <li class=md-nav__item> <a href=../../dict/filetimes/ class=md-nav__link> <span class=md-ellipsis> File timestamp </span> </a> </li> <li class=md-nav__item> <a href=../../dict/globbing/ class=md-nav__link> <span class=md-ellipsis> Globbing </span> </a> </li> <li class=md-nav__item> <a href=../../dict/hardlink/ class=md-nav__link> <span class=md-ellipsis> Hardlink </span> </a> </li> <li class=md-nav__item> <a href=../../dict/interpreter_directive/ class=md-nav__link> <span class=md-ellipsis> Interpreter Directive </span> </a> </li> <li class=md-nav__item> <a href=../../dict/parameter/ class=md-nav__link> <span class=md-ellipsis> Parameter </span> </a> </li> <li class=md-nav__item> <a href=../../dict/posix/ class=md-nav__link> <span class=md-ellipsis> POSIX </span> </a> </li> <li class=md-nav__item> <a href=../../dict/shell/ class=md-nav__link> <span class=md-ellipsis> Shell </span> </a> </li> <li class=md-nav__item> <a href=../../dict/special_file/ class=md-nav__link> <span class=md-ellipsis> Special file </span> </a> </li> <li class=md-nav__item> <a href=../../dict/symlink/ class=md-nav__link> <span class=md-ellipsis> Symlink </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_4> <label class=md-nav__link for=__nav_4 id=__nav_4_label tabindex=0> <span class=md-ellipsis> Howto </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_4_label aria-expanded=false> <label class=md-nav__title for=__nav_4> <span class="md-nav__icon md-icon"></span> Howto </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../howto/calculate-dc/ class=md-nav__link> <span class=md-ellipsis> Calculating with dc </span> </a> </li> <li class=md-nav__item> <a href=../../howto/collapsing_functions/ class=md-nav__link> <span class=md-ellipsis> Collapsing Functions </span> </a> </li> <li class=md-nav__item> <a href=../../howto/conffile/ class=md-nav__link> <span class=md-ellipsis> Config files for your script </span> </a> </li> <li class=md-nav__item> <a href=../../howto/dissectabadoneliner/ class=md-nav__link> <span class=md-ellipsis> Dissect a bad oneliner </span> </a> </li> <li class=md-nav__item> <a href=../../howto/edit-ed/ class=md-nav__link> <span class=md-ellipsis> Editing files via scripts with ed </span> </a> </li> <li class=md-nav__item> <a href=../../howto/getopts_tutorial/ class=md-nav__link> <span class=md-ellipsis> Small getopts tutorial </span> </a> </li> <li class=md-nav__item> <a href=../../howto/mutex/ class=md-nav__link> <span class=md-ellipsis> Lock your script (against parallel execution) </span> </a> </li> <li class=md-nav__item> <a href=../../howto/pax/ class=md-nav__link> <span class=md-ellipsis> pax - the POSIX archiver </span> </a> </li> <li class=md-nav__item> <a href=../../howto/redirection_tutorial/ class=md-nav__link> <span class=md-ellipsis> Illustrated Redirection Tutorial </span> </a> </li> <li class=md-nav__item> <a href=../../howto/testing-your-scripts/ class=md-nav__link> <span class=md-ellipsis> Testing your scripts </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_5> <label class=md-nav__link for=__nav_5 id=__nav_5_label tabindex=0> <span class=md-ellipsis> Internals </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_5_label aria-expanded=false> <label class=md-nav__title for=__nav_5> <span class="md-nav__icon md-icon"></span> Internals </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../internals/shell_options/ class=md-nav__link> <span class=md-ellipsis> List of shell options </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_6> <label class=md-nav__link for=__nav_6 id=__nav_6_label tabindex=0> <span class=md-ellipsis> Misc </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_6_label aria-expanded=false> <label class=md-nav__title for=__nav_6> <span class="md-nav__icon md-icon"></span> Misc </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../misc/bashphorisms/ class=md-nav__link> <span class=md-ellipsis> The Bashphorisms </span> </a> </li> <li class=md-nav__item> <a href=../../misc/readthesourceluke/ class=md-nav__link> <span class=md-ellipsis> Readthesourceluke </span> </a> </li> <li class=md-nav__item> <a href=../../misc/shell_humor/ class=md-nav__link> <span class=md-ellipsis> Shell Humor </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_7> <label class=md-nav__link for=__nav_7 id=__nav_7_label tabindex=0> <span class=md-ellipsis> Scripting </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_7_label aria-expanded=false> <label class=md-nav__title for=__nav_7> <span class="md-nav__icon md-icon"></span> Scripting </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../scripting/bashbehaviour/ class=md-nav__link> <span class=md-ellipsis> Bash's behaviour </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/bashchanges/ class=md-nav__link> <span class=md-ellipsis> Bash changes </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/basics/ class=md-nav__link> <span class=md-ellipsis> The basics of shell scripting </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/debuggingtips/ class=md-nav__link> <span class=md-ellipsis> Debugging a script </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/newbie_traps/ class=md-nav__link> <span class=md-ellipsis> Beginner Mistakes </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/nonportable/ class=md-nav__link> <span class=md-ellipsis> Portability talk </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/obsolete/ class=md-nav__link> <span class=md-ellipsis> Obsolete and deprecated syntax </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/posparams/ class=md-nav__link> <span class=md-ellipsis> Handling positional parameters </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/processtree/ class=md-nav__link> <span class=md-ellipsis> Bash and the process tree </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/style/ class=md-nav__link> <span class=md-ellipsis> Scripting with style </span> </a> </li> <li class=md-nav__item> <a href=../../scripting/terminalcodes/ class=md-nav__link> <span class=md-ellipsis> Terminal codes (ANSI/VT100) introduction </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_8> <label class=md-nav__link for=__nav_8 id=__nav_8_label tabindex=0> <span class=md-ellipsis> Snipplets </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_8_label aria-expanded=false> <label class=md-nav__title for=__nav_8> <span class="md-nav__icon md-icon"></span> Snipplets </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../../snipplets/ class=md-nav__link> <span class=md-ellipsis> Small code snipplets </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/add_color_to_your_scripts/ class=md-nav__link> <span class=md-ellipsis> Add Color to your scripts </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/awkcsv/ class=md-nav__link> <span class=md-ellipsis> Using awk to deal with CSV that uses quoted/unquoted delimiters </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/filesize/ class=md-nav__link> <span class=md-ellipsis> Show size of a file </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/kill_bg_job_without_message/ class=md-nav__link> <span class=md-ellipsis> Kill a background job without a message </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/largestfile/ class=md-nav__link> <span class=md-ellipsis> Get largest file </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/pause_command/ class=md-nav__link> <span class=md-ellipsis> Pausing a script (like MSDOS pause command) </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/prargs/ class=md-nav__link> <span class=md-ellipsis> Print argument list for testing </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/print_horizontal_line/ class=md-nav__link> <span class=md-ellipsis> Print a horizontal line </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/rndstr/ class=md-nav__link> <span class=md-ellipsis> Print a random string or select random elements </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/screen_saverestore/ class=md-nav__link> <span class=md-ellipsis> Save and restore terminal/screen content </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/ssh_fetchkeys/ class=md-nav__link> <span class=md-ellipsis> Fetching SSH hostkeys without interaction </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/ssh_local_var/ class=md-nav__link> <span class=md-ellipsis> Run some bash commands with SSH remotely using local variables </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/wrapperargs/ class=md-nav__link> <span class=md-ellipsis> Generate code with own arguments properly quoted </span> </a> </li> <li class=md-nav__item> <a href=../../snipplets/xclip/ class=md-nav__link> <span class=md-ellipsis> X-Clipboard on Commandline </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--active md-nav__item--section md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_9 checked> <label class=md-nav__link for=__nav_9 id=__nav_9_label tabindex> <span class=md-ellipsis> Syntax </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=1 aria-labelledby=__nav_9_label aria-expanded=true> <label class=md-nav__title for=__nav_9> <span class="md-nav__icon md-icon"></span> Syntax </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../arith_expr/ class=md-nav__link> <span class=md-ellipsis> Arithmetic expressions </span> </a> </li> <li class=md-nav__item> <a href=../arrays/ class=md-nav__link> <span class=md-ellipsis> Arrays </span> </a> </li> <li class="md-nav__item md-nav__item--active"> <input class="md-nav__toggle md-toggle" type=checkbox id=__toc> <label class="md-nav__link md-nav__link--active" for=__toc> <span class=md-ellipsis> Basic grammar rules of Bash </span> <span class="md-nav__icon md-icon"></span> </label> <a href=./ class="md-nav__link md-nav__link--active"> <span class=md-ellipsis> Basic grammar rules of Bash </span> </a> <nav class="md-nav md-nav--secondary" aria-label="Table of contents"> <label class=md-nav__title for=__toc> <span class="md-nav__icon md-icon"></span> Table of contents </label> <ul class=md-nav__list data-md-component=toc data-md-scrollfix> <li class=md-nav__item> <a href=#simple-commands class=md-nav__link> <span class=md-ellipsis> Simple Commands </span> </a> </li> <li class=md-nav__item> <a href=#pipelines class=md-nav__link> <span class=md-ellipsis> Pipelines </span> </a> </li> <li class=md-nav__item> <a href=#lists class=md-nav__link> <span class=md-ellipsis> Lists </span> </a> </li> <li class=md-nav__item> <a href=#compound-commands class=md-nav__link> <span class=md-ellipsis> Compound Commands </span> </a> </li> <li class=md-nav__item> <a href=#shell-function-definitions class=md-nav__link> <span class=md-ellipsis> Shell Function Definitions </span> </a> </li> <li class=md-nav__item> <a href=#grammar-summary class=md-nav__link> <span class=md-ellipsis> Grammar summary </span> </a> </li> <li class=md-nav__item> <a href=#examples-for-classification class=md-nav__link> <span class=md-ellipsis> Examples for classification </span> </a> </li> <li class=md-nav__item> <a href=#see-also class=md-nav__link> <span class=md-ellipsis> See also </span> </a> </li> </ul> </nav> </li> <li class=md-nav__item> <a href=../pattern/ class=md-nav__link> <span class=md-ellipsis> Patterns and pattern matching </span> </a> </li> <li class=md-nav__item> <a href=../pe/ class=md-nav__link> <span class=md-ellipsis> Parameter expansion </span> </a> </li> <li class=md-nav__item> <a href=../quoting/ class=md-nav__link> <span class=md-ellipsis> Quotes and escaping </span> </a> </li> <li class=md-nav__item> <a href=../redirection/ class=md-nav__link> <span class=md-ellipsis> Redirection </span> </a> </li> <li class=md-nav__item> <a href=../shellvars/ class=md-nav__link> <span class=md-ellipsis> Special parameters and shell variables </span> </a> </li> <li class=md-nav__item> <a href=../words/ class=md-nav__link> <span class=md-ellipsis> Words... </span> </a> </li> <li class="md-nav__item md-nav__item--section md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_9_10> <label class=md-nav__link for=__nav_9_10 id=__nav_9_10_label tabindex> <span class=md-ellipsis> Ccmd </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=2 aria-labelledby=__nav_9_10_label aria-expanded=false> <label class=md-nav__title for=__nav_9_10> <span class="md-nav__icon md-icon"></span> Ccmd </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../ccmd/arithmetic_eval/ class=md-nav__link> <span class=md-ellipsis> Arithmetic evaluation (command) </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/c_for/ class=md-nav__link> <span class=md-ellipsis> The C-style for-loop </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/case/ class=md-nav__link> <span class=md-ellipsis> The case statement </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/classic_for/ class=md-nav__link> <span class=md-ellipsis> The classic for-loop </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/conditional_expression/ class=md-nav__link> <span class=md-ellipsis> The conditional expression </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/grouping_plain/ class=md-nav__link> <span class=md-ellipsis> Grouping commands </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/grouping_subshell/ class=md-nav__link> <span class=md-ellipsis> Grouping commands in a subshell </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/if_clause/ class=md-nav__link> <span class=md-ellipsis> The if-clause </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/intro/ class=md-nav__link> <span class=md-ellipsis> Bash compound commands </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/until_loop/ class=md-nav__link> <span class=md-ellipsis> The until loop </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/user_select/ class=md-nav__link> <span class=md-ellipsis> User selections </span> </a> </li> <li class=md-nav__item> <a href=../ccmd/while_loop/ class=md-nav__link> <span class=md-ellipsis> The while-loop </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--section md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_9_11> <label class=md-nav__link for=__nav_9_11 id=__nav_9_11_label tabindex> <span class=md-ellipsis> Expansion </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=2 aria-labelledby=__nav_9_11_label aria-expanded=false> <label class=md-nav__title for=__nav_9_11> <span class="md-nav__icon md-icon"></span> Expansion </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../expansion/arith/ class=md-nav__link> <span class=md-ellipsis> Arithmetic expansion </span> </a> </li> <li class=md-nav__item> <a href=../expansion/brace/ class=md-nav__link> <span class=md-ellipsis> Brace expansion </span> </a> </li> <li class=md-nav__item> <a href=../expansion/cmdsubst/ class=md-nav__link> <span class=md-ellipsis> Command substitution </span> </a> </li> <li class=md-nav__item> <a href=../expansion/globs/ class=md-nav__link> <span class=md-ellipsis> Pathname expansion (globbing) </span> </a> </li> <li class=md-nav__item> <a href=../expansion/intro/ class=md-nav__link> <span class=md-ellipsis> Expansions and substitutions </span> </a> </li> <li class=md-nav__item> <a href=../expansion/proc_subst/ class=md-nav__link> <span class=md-ellipsis> Process substitution </span> </a> </li> <li class=md-nav__item> <a href=../expansion/tilde/ class=md-nav__link> <span class=md-ellipsis> Tilde expansion </span> </a> </li> <li class=md-nav__item> <a href=../expansion/wordsplit/ class=md-nav__link> <span class=md-ellipsis> Word splitting </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--section md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_9_12> <label class=md-nav__link for=__nav_9_12 id=__nav_9_12_label tabindex> <span class=md-ellipsis> Grammar </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=2 aria-labelledby=__nav_9_12_label aria-expanded=false> <label class=md-nav__title for=__nav_9_12> <span class="md-nav__icon md-icon"></span> Grammar </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../grammar/parser_exec/ class=md-nav__link> <span class=md-ellipsis> Parser exec </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--section md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type=checkbox id=__nav_9_13> <label class=md-nav__link for=__nav_9_13 id=__nav_9_13_label tabindex> <span class=md-ellipsis> Keywords </span> <span class="md-nav__icon md-icon"></span> </label> <nav class=md-nav data-md-level=2 aria-labelledby=__nav_9_13_label aria-expanded=false> <label class=md-nav__title for=__nav_9_13> <span class="md-nav__icon md-icon"></span> Keywords </label> <ul class=md-nav__list data-md-scrollfix> <li class=md-nav__item> <a href=../keywords/coproc/ class=md-nav__link> <span class=md-ellipsis> The coproc keyword </span> </a> </li> </ul> </nav> </li> </ul> </nav> </li> <li class=md-nav__item> <a href=../../tags/ class=md-nav__link> <span class=md-ellipsis> Tags </span> </a> </li> </ul> </nav> </div> </div> </div> <div class="md-sidebar md-sidebar--secondary" data-md-component=sidebar data-md-type=toc> <div class=md-sidebar__scrollwrap> <div class=md-sidebar__inner> <nav class="md-nav md-nav--secondary" aria-label="Table of contents"> <label class=md-nav__title for=__toc> <span class="md-nav__icon md-icon"></span> Table of contents </label> <ul class=md-nav__list data-md-component=toc data-md-scrollfix> <li class=md-nav__item> <a href=#simple-commands class=md-nav__link> <span class=md-ellipsis> Simple Commands </span> </a> </li> <li class=md-nav__item> <a href=#pipelines class=md-nav__link> <span class=md-ellipsis> Pipelines </span> </a> </li> <li class=md-nav__item> <a href=#lists class=md-nav__link> <span class=md-ellipsis> Lists </span> </a> </li> <li class=md-nav__item> <a href=#compound-commands class=md-nav__link> <span class=md-ellipsis> Compound Commands </span> </a> </li> <li class=md-nav__item> <a href=#shell-function-definitions class=md-nav__link> <span class=md-ellipsis> Shell Function Definitions </span> </a> </li> <li class=md-nav__item> <a href=#grammar-summary class=md-nav__link> <span class=md-ellipsis> Grammar summary </span> </a> </li> <li class=md-nav__item> <a href=#examples-for-classification class=md-nav__link> <span class=md-ellipsis> Examples for classification </span> </a> </li> <li class=md-nav__item> <a href=#see-also class=md-nav__link> <span class=md-ellipsis> See also </span> </a> </li> </ul> </nav> </div> </div> </div> <div class=md-content data-md-component=content> <article class="md-content__inner md-typeset"> <nav class=md-tags> <a href=../../tags/#bash class=md-tag>bash</a> <a href=../../tags/#shell class=md-tag>shell</a> <a href=../../tags/#scripting class=md-tag>scripting</a> <a href=../../tags/#grammar class=md-tag>grammar</a> <a href=../../tags/#syntax class=md-tag>syntax</a> <a href=../../tags/#language class=md-tag>language</a> </nav> <a href=https://github.com/flokoe/bash-hackers-wiki/edit/main/docs/syntax/basicgrammar.md title="Edit this page" class="md-content__button md-icon"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4zm10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1z"/></svg> </a> <a href=https://github.com/flokoe/bash-hackers-wiki/raw/main/docs/syntax/basicgrammar.md title="View source of this page" class="md-content__button md-icon"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M17 18c.56 0 1 .44 1 1s-.44 1-1 1-1-.44-1-1 .44-1 1-1m0-3c-2.73 0-5.06 1.66-6 4 .94 2.34 3.27 4 6 4s5.06-1.66 6-4c-.94-2.34-3.27-4-6-4m0 6.5a2.5 2.5 0 0 1-2.5-2.5 2.5 2.5 0 0 1 2.5-2.5 2.5 2.5 0 0 1 2.5 2.5 2.5 2.5 0 0 1-2.5 2.5M9.27 20H6V4h7v5h5v4.07c.7.08 1.36.25 2 .49V8l-6-6H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h4.5a8.2 8.2 0 0 1-1.23-2"/></svg> </a> <h1 id=basic-grammar-rules-of-bash>Basic grammar rules of Bash<a class=headerlink href=#basic-grammar-rules-of-bash title="Permanent link">¶</a></h1> <p>Bash builds its features on top of a few basic <strong>grammar rules</strong>. The code you see everywhere, the code you use, is based on those rules. However, <strong>this is a very theoretical view</strong>, but if you're interested, it may help you understand why things look the way they look.</p> <p>If you don't know the commands used in the following examples, just trust the explanation.</p> <h2 id=simple-commands>Simple Commands<a class=headerlink href=#simple-commands title="Permanent link">¶</a></h2> <p>Bash manual says:</p> <div class=highlight><pre><span></span><code>A simple command is a sequence of optional variable assignments followed by blank-separated words and redirections,
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and terminated by a control operator. The first word specifies the command to be executed, and is passed as argument
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zero. The remaining words are passed as arguments to the invoked command.
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</code></pre></div> <p>Sounds harder than it actually is. It is what you do daily. You enter simple commands with parameters, and the shell executes them.</p> <p>Every complex Bash operation can be split into simple commands:</p> <div class=highlight><pre><span></span><code>ls
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ls > list.txt
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ls -l
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LC_ALL=C ls
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</code></pre></div> <p>The last one might not be familiar. That one simply adds "<code>LC_ALL=C</code>" to the environment of the <code>ls</code> program. It doesn't affect your current shell. This also works while calling functions, unless Bash runs in POSIX® mode (in which case it affects your current shell).</p> <p>Every command has an exit code. It's a type of return status. The shell can catch it and act on it. Exit code range is from 0 to 255, where 0 means success, and the rest mean either something failed, or there is an issue to report back to the calling program.</p> <div class="admonition info"> <p class=admonition-title>info</p> <p>The simple command construct is the <strong>base</strong> for all higher constructs. Everything you execute, from pipelines to functions, finally ends up in (many) simple commands. That's why Bash only has one method to <a href=../grammar/parser_exec/ >expand and execute a simple command</a>.</p> </div> <h2 id=pipelines>Pipelines<a class=headerlink href=#pipelines title="Permanent link">¶</a></h2> <div class="admonition warning"> <p class=admonition-title>FIXME</p> <p>Missing an additional article about pipelines and pipelining</p> </div> <p><code>[time [-p]] [ ! ] command [ | command2 ... ]</code></p> <p><strong>Don't get confused</strong> about the name "pipeline." It's a grammatic name for a construct. Such a pipeline isn't necessarily a pair of commands where stdout/stdin is connected via a real pipe.</p> <p>Pipelines are one or more <a href=#simple-commands>simple commands</a> (separated by the <code>|</code> symbol connects their input and output), for example:</p> <div class=highlight><pre><span></span><code>ls /etc | wc -l
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</code></pre></div> <p>will execute <code>ls</code> on <code>/etc</code> and <strong>pipe</strong> the output to <code>wc</code>, which will count the lines generated by the ls command. The result is the number of directory entries in /etc.</p> <p>The last command in the pipeline will set the exit code for the pipeline. This exit code can be "inverted" by prefixing an exclamation mark to the pipeline: An unsuccessful pipeline will exit "successful" and vice versa. In this example, the commands in the if stanza will be executed if the pattern "^root:" is <strong>not</strong> found in <code>/etc/passwd</code>:</p> <div class=highlight><pre><span></span><code>if ! grep '^root:' /etc/passwd; then
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echo "No root user defined... eh?"
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fi
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</code></pre></div> <p>Yes, this is also a pipeline (although there is no pipe!), because the <strong>exclamation mark to invert the exit code</strong> can only be used in a pipeline. If <code>grep</code>'s exit code is 1 (FALSE) (the text was not found), the leading <code>!</code> will "invert" the exit code, and the shell sees (and acts on) exit code 0 (TRUE) and the <code>then</code> part of the <code>if</code> stanza is executed. One could say we checked for "<code>not grep "^root" /etc/passwd</code>".</p> <p>The <a href=../../commands/builtin/set/#attributes>set option pipefail</a> determines the behavior of how bash reports the exit code of a pipeline. If it's set, then the exit code (<code>$?</code>) is the last command that exits with non zero status, if none fail, it's zero. If it's not set, then <code>$?</code> always holds the exit code of the last command (as explained above).</p> <p>The shell option <code>lastpipe</code> will execute the last element in a pipeline construct in the current shell environment, i.e. not a subshell.</p> <p>There's also an array <code>PIPESTATUS[]</code> that is set after a foreground pipeline is executed. Each element of <code>PIPESTATUS[]</code> reports the exit code of the respective command in the pipeline. Note: (1) it's only for foreground pipe and (2) for higher level structure that is built up from a pipeline. Like list, <code>PIPESTATUS[]</code> holds the exit status of the last pipeline command executed.</p> <p>Another thing you can do with pipelines is log their execution time. Note that <strong><code>time</code> is not a command</strong>, it is part of the pipeline syntax:</p> <div class=highlight><pre><span></span><code># time updatedb
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real 3m21.288s
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user 0m3.114s
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sys 0m4.744s
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</code></pre></div> <h2 id=lists>Lists<a class=headerlink href=#lists title="Permanent link">¶</a></h2> <div class="admonition warning"> <p class=admonition-title>FIXME</p> <p>Missing an additional article about list operators</p> </div> <p>A list is a sequence of one or more <a href=#pipelines>pipelines</a> separated by one of the operators <code>;</code>, <code>&</code>, <code>&&</code>, or <code>││</code>, and optionally terminated by one of <code>;</code>, <code>&</code>, or <code><newline></code>.</p> <p>=> It's a group of <strong>pipelines</strong> separated or terminated by <strong>tokens</strong> that all have <strong>different meanings</strong> for Bash.</p> <p>Your whole Bash script technically is one big single list!</p> <table> <thead> <tr> <th>Operator</th> <th>Description</th> </tr> </thead> <tbody> <tr> <td><code><PIPELINE1> <newline> <PIPELINE2></code></td> <td>Newlines completely separate pipelines. The next pipeline is executed without any checks. (You enter a command and press <code><RETURN></code>!)</td> </tr> <tr> <td><code><PIPELINE1> ; <PIPELINE2></code></td> <td>The semicolon does what <code><newline></code> does: It separates the pipelines</td> </tr> <tr> <td><code><PIPELINE> & <PIPELINE></code></td> <td>The pipeline in front of the <code>&</code> is executed <strong>asynchronously</strong> ("in the background"). If a pipeline follows this, it is executed immediately after the async pipeline starts</td> </tr> <tr> <td><code><PIPELINE1> && <PIPELINE2></code></td> <td><code><PIPELINE1></code> is executed and <strong>only</strong> if its exit code was 0 (TRUE), then <code><PIPELINE2></code> is executed (AND-List)</td> </tr> <tr> <td><code><PIPELINE1>||<PIPELINE2></code></td> <td><code><PIPELINE1></code> is executed and <strong>only</strong> if its exit code was <strong>not</strong> 0 (FALSE), then <code><PIPELINE2></code> is executed (OR-List)</td> </tr> </tbody> </table> <p><strong>Note:</strong> POSIX calls this construct a "compound lists".</p> <h2 id=compound-commands>Compound Commands<a class=headerlink href=#compound-commands title="Permanent link">¶</a></h2> <p>See also the <a href=../ccmd/intro/ >list of compound commands</a>.</p> <p>There are two forms of compound commands:</p> <ul> <li>form a new syntax element using a list as a "body"</li> <li>completly independant syntax elements</li> </ul> <p>Essentially, everything else that's not described in this article. Compound commands have the following characteristics:</p> <ul> <li>they <strong>begin</strong> and <strong>end</strong> with a specific keyword or operator (e.g. <code>for ... done</code>)</li> <li>they can be redirected as a whole</li> </ul> <p>See the following table for a short overview (no details - just an overview):</p> <table> <thead> <tr> <th>Compound command syntax</th> <th>Description</th> </tr> </thead> <tbody> <tr> <td><code>( <LIST> )</code></td> <td>Execute <code><LIST></code> in an extra subshell => <a href=../ccmd/grouping_subshell/ >article</a></td> </tr> <tr> <td><code>{ <LIST> ; }</code></td> <td>Execute <code><LIST></code> as separate group (but not in a subshell) => <a href=../ccmd/grouping_plain/ >article</a></td> </tr> <tr> <td><code>(( <EXPRESSION> ))</code></td> <td>Evaluate the arithmetic expression <code><EXPRESSION></code> => <a href=../ccmd/arithmetic_eval/ >article</a></td> </tr> <tr> <td><code>[[ <EXPRESSION> ]]</code></td> <td>Evaluate the conditional expression <code><EXPRESSION></code> (aka "the new test command") => <a href=../ccmd/conditional_expression/ >article</a></td> </tr> <tr> <td><code>for <NAME> in <WORDS> ; do <LIST> ; done</code></td> <td>Executes <code><LIST></code> while setting the variable <code><NAME></code> to one of <code><WORDS></code> on every iteration (classic for-loop) => <a href=../ccmd/classic_for/ >article</a></td> </tr> <tr> <td><code>for (( <EXPR1> ; <EXPR2> ; <EXPR3> )) ; do <LIST> ; done</code></td> <td>C-style for-loop (driven by arithmetic expressions) => <a href=../ccmd/c_for/ >article</a></td> </tr> <tr> <td><code>select <NAME> in <WORDS> ; do <LIST> ; done</code></td> <td>Provides simple menus => <a href=../ccmd/user_select/ >article</a></td> </tr> <tr> <td><code>case <WORD> in <PATTERN>) <LIST> ;; ... esac</code></td> <td>Decisions based on pattern matching - executing <code><LIST></code> on match => <a href=../ccmd/case/ >article</a></td> </tr> <tr> <td><code>if <LIST> ; then <LIST> ; else <LIST> ; fi</code></td> <td>The if clause: makes decisions based on exit codes => <a href=../ccmd/if_clause/ >article</a></td> </tr> <tr> <td><code>while <LIST1> ; do <LIST2> ; done</code></td> <td>Execute <code><LIST2></code> while <code><LIST1></code> returns TRUE (exit code) => <a href=../ccmd/while_loop/ >article</a></td> </tr> <tr> <td><code>until <LIST1> ; do <LIST2> ; done</code></td> <td>Execute <code><LIST2></code> until <code><LIST1></code> returns TRUE (exit code) => <a href=../ccmd/until_loop/ >article</a></td> </tr> </tbody> </table> <h2 id=shell-function-definitions>Shell Function Definitions<a class=headerlink href=#shell-function-definitions title="Permanent link">¶</a></h2> <div class="admonition warning"> <p class=admonition-title>FIXME</p> <p>Missing an additional article about shell functions</p> </div> <p>A shell function definition makes a <a href=#compound_commands>compound command</a> available via a new name. When the function runs, it has its own "private" set of positional parameters and I/O descriptors. It acts like a script-within-the-script. Simply stated: <strong>You've created a new command.</strong></p> <p>The definition is easy (one of many possibilities):</p> <p><code><NAME> () <COMPOUND_COMMAND> <REDIRECTIONS></code></p> <p>which is usually used with the <code>{...; }</code> compound command, and thus looks like:</p> <div class=highlight><pre><span></span><code>print_help() { echo "Sorry, no help available"; }
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</code></pre></div> <p>As above, a function definition can have any <a href=#compound_commands>compound command</a> as a body. Structures like</p> <div class=highlight><pre><span></span><code>countme() for ((x=1;x<=9;x++)); do echo $x; done
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</code></pre></div> <p>are unusual, but perfectly valid, since the for loop construct is a compound command!</p> <p>If <strong>redirection</strong> is specified, the redirection is not performed when the function is defined. It is performed when the function runs:</p> <div class=highlight><pre><span></span><code># this will NOT perform the redirection (at definition time)
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f() { echo ok ; } > file
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# NOW the redirection will be performed (during EXECUTION of the function)
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f
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</code></pre></div> <p>Bash allows three equivalent forms of the function definition:</p> <div class=highlight><pre><span></span><code>NAME () <COMPOUND_COMMAND> <REDIRECTIONS>
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function NAME () <COMPOUND_COMMAND> <REDIRECTIONS>
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function NAME <COMPOUND_COMMAND> <REDIRECTIONS>
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</code></pre></div> <p>The space between <code>NAME</code> and <code>()</code> is optional, usually you see it without the space.</p> <p>I suggest using the first form. It's specified in POSIX and all Bourne-like shells seem to support it.</p> <p><u><strong>Note:</strong></u> Before version <code>2.05-alpha1</code>, Bash only recognized the definition using curly braces (<code>name() { ... }</code>), other shells allow the definition using <strong>any</strong> command (not just the compound command set).</p> <p>To execute a function like a regular shell script you put it together like this:</p> <div class=highlight><pre><span></span><code>#!/bin/bash
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# Add shebang
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mycmd()
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{
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# this $1 belongs to the function!
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find / -iname "$1"
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}
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# this $1 belongs the script itself!
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mycmd "$1" # Execute command immediately after defining function
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exit 0
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</code></pre></div> <p><strong>Just informational(1):</strong></p> <p>Internally, for forking, Bash stores function definitions in environment variables. Variables with the content "<em>() ....</em>".</p> <p>Something similar to the following works without "officially" declaring a function:</p> <div class=highlight><pre><span></span><code>$ export testfn="() { echo test; }"
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$ bash -c testfn
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test
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$
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</code></pre></div> <p><strong>Just informational(2):</strong></p> <p>It is possible to create function names containing slashes:</p> <div class=highlight><pre><span></span><code>/bin/ls() {
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echo LS FAKE
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}
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</code></pre></div> <p>The elements of this name aren't subject to a path search.</p> <p>Weird function names should not be used. Quote from the maintainer:</p> <ul> <li> <ul> <li>It was a mistake to allow such characters in function names (<code>unset</code> doesn't work to unset them without forcing <code>-f</code>, for instance). We're stuck with them for backwards compatibility, but I don't have to encourage their use. *</li> </ul> </li> </ul> <h2 id=grammar-summary>Grammar summary<a class=headerlink href=#grammar-summary title="Permanent link">¶</a></h2> <ul> <li>a <a href=#simple_commands>simple command</a> is just a command and its arguments</li> <li>a <a href=#pipelines>pipeline</a> is one or more <a href=#simple_commands>simple command</a> probably connected in a pipe</li> <li>a <a href=#lists>list</a> is one or more <a href=#pipelines>pipelines</a> connected by special operators</li> <li>a <a href=#compound_commands>compound command</a> is a <a href=#lists>list</a> or a special command that forms a new meta-command</li> <li>a <a href=#shell_function_definitions>function definition</a> makes a <a href=#compound_commands>compound command</a> available under a new name, and a separate environment</li> </ul> <h2 id=examples-for-classification>Examples for classification<a class=headerlink href=#examples-for-classification title="Permanent link">¶</a></h2> <div class="admonition warning"> <p class=admonition-title>FIXME</p> <p>more...</p> </div> <hr> <p><u>A (very) simple command</u></p> <div class=highlight><pre><span></span><code>echo "Hello world..."
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</code></pre></div> <p><u>All of the following are simple commands</u></p> <div class=highlight><pre><span></span><code>x=5
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>tmpfile
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{x}<"$x" _=${x=<(echo moo)} <&0$(cat <&"$x" >&2)
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</code></pre></div> <hr> <p><u>A common compound command</u></p> <div class=highlight><pre><span></span><code>if [ -d /data/mp3 ]; then
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cp mymusic.mp3 /data/mp3
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fi
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</code></pre></div> <ul> <li>the <a href=#compound_commands>compound command</a> for the <code>if</code> clause</li> <li>the <a href=#lists>list</a> that <code>if</code> <strong>checks</strong> actually contains the <a href=#simple_commands>simple command</a> <code>[ -d /data/mp3 ]</code></li> <li>the <a href=#lists>list</a> that <code>if</code> <strong>executes</strong> contains a simple command (<code>cp mymusic.mp3 /data/mp3</code>)</li> </ul> <p>Let's invert test command exit code, only one thing changes:</p> <div class=highlight><pre><span></span><code>if ! [ -d /data/mp3 ]; then
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cp mymusic.mp3 /data/mp3
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fi
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</code></pre></div> <ul> <li>the <a href=#lists>list</a> that <code>if</code> <strong>checks</strong> contains a <a href=#pipelines>pipeline</a> now (because of the <code>!</code>)</li> </ul> <h2 id=see-also>See also<a class=headerlink href=#see-also title="Permanent link">¶</a></h2> <ul> <li>Internal: <a href=../ccmd/intro/ >List of compound commands</a></li> <li>Internal: <a href=../grammar/parser_exec/ >Parsing and execution of simple commands</a></li> <li>Internal: <a href=../quoting/ >Quoting and escaping</a></li> <li>Internal: <a href=../expansion/intro/ >Introduction to expansions and substitutions</a></li> <li>Internal: <a href=../words/ >Some words about words...</a></li> </ul> <aside class=md-source-file> <span class=md-source-file__fact> <span class=md-icon title="Last update"> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1zM12.5 7v5.2l4 2.4-1 1L11 13V7zM11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date">November 13, 2024</span> </span> <span class=md-source-file__fact> <span class=md-icon title=Created> <svg xmlns=http://www.w3.org/2000/svg viewbox="0 0 24 24"><path d="M14.47 15.08 11 13V7h1.5v5.25l3.08 1.83c-.41.28-.79.62-1.11 1m-1.39 4.84c-.36.05-.71.08-1.08.08-4.42 0-8-3.58-8-8s3.58-8 8-8 8 3.58 8 8c0 .37-.03.72-.08 1.08.69.1 1.33.32 1.92.64.1-.56.16-1.13.16-1.72 0-5.5-4.5-10-10-10S2 6.5 2 12s4.47 10 10 10c.59 0 1.16-.06 1.72-.16-.32-.59-.54-1.23-.64-1.92M18 15v3h-3v2h3v3h2v-3h3v-2h-3v-3z"/></svg> </span> <span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date">November 13, 2024</span> </span> </aside> <h2 id=__comments>Comments</h2> <script src=https://giscus.app/client.js data-repo=flokoe/bash-hackers-wiki data-repo-id=R_kgDOJ3Nr6Q data-category="Giscus Page Comments" data-category-id=DIC_kwDOJ3Nr6c4CXq9t data-mapping=pathname data-strict=1 data-reactions-enabled=1 data-emit-metadata=0 data-input-position=top data-theme=preferred_color_scheme data-lang=en data-loading=lazy crossorigin=anonymous async>
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var theme = palette.color.scheme === "slate" ? "dark" : "light"
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|
giscus.setAttribute("data-theme", theme)
|
|
}
|
|
|
|
/* Register event handlers after documented loaded */
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|
document.addEventListener("DOMContentLoaded", function() {
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|
var ref = document.querySelector("[data-md-component=palette]")
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ref.addEventListener("change", function() {
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|
var palette = __md_get("__palette")
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|
if (palette && typeof palette.color === "object") {
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|
var theme = palette.color.scheme === "slate" ? "dark" : "light"
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|
|
|
/* Instruct Giscus to change theme */
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|
var frame = document.querySelector(".giscus-frame")
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|
frame.contentWindow.postMessage(
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|
{ giscus: { setConfig: { theme } } },
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|
"https://giscus.app"
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|
)
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|
}
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|
})
|
|
})
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|
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