BASH FAQ

BASH FAQ

  • What is it?

    What is it? Bash is a Unix command interpreter (shell). It is an implementation o

  • What is the bash `posix mode'?

    What is the bash `posix mode'? Although bash is an implementation of the POSIX.2 s

  • What's the latest version?

    What's the latest version? The latest version is 2.05a, first made available on Th

  • Where can I get it?

    Where can I get it? Bash is the GNU project's shell, and so is available from the

  • On what machines will bash run?

    On what machines will bash run? Bash has been ported to nearly every version of UN

  • Will bash run on operating systems other than Unix?

    Will bash run on operating systems other than Unix? Configuration specifics for Uni

  • How can I build bash with gcc?

    How can I build bash with gcc? Bash configures to use gcc by default if it is avai

  • How can I make bash my login shell?

    How can I make bash my login shell? Some machines let you use `chsh' to change you

  • I just changed my login shell to bash, and now I can't FTP into my

    machine. Why not? I just changed my login shell to bash, and now I can't FTP into my

  • What's the `POSIX 1003.2 standard'?

    What's the `POSIX 1003.2 standard'? POSIX is a name originally coined by Richard S

  • What's new in version 2.05a?

    What's new in version 2.05a? The raison d'etre for bash-2.05a is to make an interme

  • Are there any user-visible incompatibilities between bash-2.05a and

    bash-1.14.7? Are there any user-visible incompatibilities between bash-2.05a and

  • How does bash differ from sh, the Bourne shell?

    How does bash differ from sh, the Bourne shell? This is a non-comprehensive list of

  • How does bash differ from the Korn shell, version ksh88?

    How does bash differ from the Korn shell, version ksh88? Things bash has or uses t

  • Which new features in ksh-93 are not in bash, and which are?

    Which new features in ksh-93 are not in bash, and which are? New things in ksh-93

  • Why does bash run a different version of `command' than

    `which command' says it will? Why does bash run a different version of `command' tha

  • Why doesn't bash treat brace expansions exactly like csh?

    Why doesn't bash treat brace expansions exactly like csh? The only difference betwe

  • Why doesn't bash have csh variable modifiers?

    Why doesn't bash have csh variable modifiers? Posix has specified a more powerful,

  • How can I make my csh aliases work when I convert to bash?

    How can I make my csh aliases work when I convert to bash? Bash uses a different sy

  • How can I pipe standard output and standard error from one command to

    another, like csh does with `|&'? How can I pipe standard output and standard error

  • Now that I've converted from ksh to bash, are there equivalents to

    ksh features like autoloaded functions and the `whence' command? Now that I've conve

  • Why is the bash builtin `test' slightly different from /bin/test?

    Why is the bash builtin `test' slightly different from /bin/test? The specific exam

  • Why does `cd //' leave $PWD as `//'?

    Why does `cd //' leave $PWD as `//'? POSIX.2, in its description of `cd', says that

  • Why does bash sometimes say `Broken pipe'?

    Why does bash sometimes say `Broken pipe'? If a sequence of commands appears in a p

  • When I have terminal escape sequences in my prompt, why does bash

    wrap lines at the wrong column? When I have terminal escape sequences in my prompt,

  • If I pipe the output of a command into `read variable', why doesn't

    the output show up in $variable when the read command finishes? If I pipe the output

  • I have a bunch of shell scripts that use backslash-escaped characters

    in arguments to `echo'. Bash doesn't interpret these characters. Why not, and how can I

  • Why doesn't a while or for loop get suspended when I type ^Z?

    Why doesn't a while or for loop get suspended when I type ^Z? This is a consequence

  • What about empty for loops in Makefiles?

    What about empty for loops in Makefiles? It's fairly common to see constructs like

  • Why does the arithmetic evaluation code complain about `08'?

    Why does the arithmetic evaluation code complain about `08'? The bash arithmetic ev

  • Why does the pattern matching expression [A-Z]* match files beginning

    with every letter except `z'? Why does the pattern matching expression [A-Z]* match

  • Why can't I use command line editing in my `cmdtool'?

    Why can't I use command line editing in my `cmdtool'? The problem is `cmdtool' and

  • I built bash on Solaris 2. Why do globbing expansions and filename

    completion chop off the first few characters of each filename? I built bash on Solar

  • Why does bash dump core after I interrupt username completion or

    `~user' tilde expansion on a machine running NIS? Why does bash dump core after I in

  • I'm running SVR4.2. Why is the line erased every time I type `@'?

    I'm running SVR4.2. Why is the line erased every time I type `@'? The `@' characte

  • Why does bash report syntax errors when my C News scripts use a

    redirection before a subshell command? Why does bash report syntax errors when my C

  • Why can't I use vi-mode editing on Red Hat Linux 6.1?

    Why can't I use vi-mode editing on Red Hat Linux 6.1? The short answer is that Red

  • Why does bash-2.05a fail to compile `printf.def' on HP/UX 11.x?

    Why does bash-2.05a fail to compile `printf.def' on HP/UX 11.x? HP/UX's support for

  • How can I get bash to read and display eight-bit characters?

    How can I get bash to read and display eight-bit characters? This is a process requ

  • How do I write a function `x' to replace builtin command `x', but

    still invoke the command from within the function? How do I write a function `x' to

  • How can I find the value of a shell variable whose name is the value

    of another shell variable? How can I find the value of a shell variable whose name i

  • How can I make the bash `time' reserved word print timing output that

    looks like the output from my system's /usr/bin/time? How can I make the bash `time

  • How do I get the current directory into my prompt?

    How do I get the current directory into my prompt? Bash provides a number of backsl

  • How can I rename "*.foo" to "*.bar"?

    How can I rename "*.foo" to "*.bar"? Use the pattern removal functionality describe

  • How can I translate a filename from uppercase to lowercase?

    How can I translate a filename from uppercase to lowercase? The script examples/fun

  • How can I write a filename expansion (globbing

    How can I write a filename expansion (globbing You must have set the `extglob' shell optio

  • How do I report bugs in bash, and where should I look for fixes and

    advice? How do I report bugs in bash, and where should I look for fixes and adv

  • What kind of bash documentation is there?

    What kind of bash documentation is there? First, look in the doc directory in the b

  • What's coming in future versions?

    What's coming in future versions? These are features I hope to include in a future

  • What's on the bash `wish list' for future versions?

    What's on the bash `wish list' for future versions? These are features that may or

  • When will the next release appear?

    When will the next release appear? The next version will appear sometime in 2002.

  • Credits This is the Bash FAQ, version 3.19, for Bash version 2.05a.

    This document contains a set of frequently-asked questions concerning Bash, the GNU Bou


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