42sh/builtins
Builtins
- 3.1.1 alias
- 3.1.2 bg
- 3.1.3 cd
- 3.1.3.1 Options
- 3.1.4 echo
- 3.1.5 env
- 3.1.5.1 Options
- 3.1.6 exit [n]
- 3.1.7 export
- 3.1.7.1 Options
- 3.1.8 false
- 3.1.9 fg
- 3.1.10 hash
- 3.1.10.1 Options
- 3.1.11 history
- 3.1.11.1 Options
- 3.1.12 jobs
- 3.1.12.1 Options
- 3.1.13 set
- 3.1.14 test
- 3.1.14.1 Options
- 3.1.15 true
- 3.1.16 type
- 3.1.17 unalias
- 3.1.17.1 Options
- 3.1.18 unset
- 3.1.19 fc
- 3.1.19.1 Options
3.1.1 alias
Without arguments, alias prints the list of aliases on the standard output. If arguments are supplied, an alias is defined for each name whose value is given. If no value is given, the name and value of the alias is printed.
3.1.2 bg
Resume each suspended job in the background, as if it had been started with &.
3.1.3 cd
Change the current working directory to directory. If directory is not supplied, the value of the HOME shell variable is used.
3.1.3.1 Options
-L: symbolic links in directory are resolved after cd processes an instance of ‘..’ in directory.
-P: not follow symbolic links: symbolic links are resolved while cd is traversing directory and before processing an instance of ‘..’ in directory.
3.1.4 echo
Outputs it's args to stdout, separated by spaces, followed by a newline. The return status is always 0.
3.1.5 env
Set the environment for command invocation.
3.1.5.1 Options
-i: Invoke utility with exactly the environment specified by the arguments; the inherited environment shall be ignored completely.
3.1.6 exit [n]
Shall cause the shell to exit with the exit status specified by the unsigned decimal integer n.
3.1.7 export
Marks an environment variable to be exported with any newly forked child processes and thus it allows a child process to inherit all marked variables.
3.1.7.1 Options
-p: List of all names that are exported in the current shell.
3.1.8 false
Do nothing, returning a non-zero (false) exit status.
3.1.9 fg
Put each specified job in the background, or the current job if none is specified.
3.1.10 hash
Determine and remember the full pathname of each commandname. If no arguments are given, display information about remembered command locations.
3.1.10.1 Options
-r: Forget all remembered locations.
3.1.11 history
With no options, display the history list with line numbers.
3.1.11.1 Options
-c: Clear the history list.
-d [offset]: Delete the history entry at position offset. offset should be specified as it appears when the history is displayed.
3.1.12 jobs
The first form lists the active jobs.
3.1.12.1 Options
-p: List only the process ID of the job’s process group leader.
3.1.13 set
Change the value of a shell option and set the positional parameters, or display the names and values of shell variables.
3.1.14 test
Evaluate a conditional expression.
3.1.14.1 Options
-b [pathname]: True if pathname resolves to an existing directory entry for a block special file. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a block special file.
-c [pathname]: True if pathname resolves to an existing directory entry for a character special file. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a character special file.
-d [pathname]: True if pathname resolves to an existing directory entry for a directory. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a directory.
-e [pathname]: True if pathname resolves to an existing directory entry. False if pathname cannot be resolved.
-f [pathname]: True if pathname resolves to an existing directory entry for a regular file. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a regular file.
-g [pathname]: True if pathname resolves to an existing directory entry for a file that has its set-group-ID flag set. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that does not have its set-group-ID flag set.
-L [pathname]: True if pathname resolves to an existing directory entry for a symbolic link. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a symbolic link. If the final component of pathname is a symbolic link, that symbolic link is not followed.
-p [pathname]: True if pathname resolves to an existing directory entry for a FIFO. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a FIFO.
-r [pathname]: True if pathname resolves to an existing directory entry for a file for which permission to read from the file will be granted, as defined in File Read, Write, and Creation. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file for which permission to read from the file will not be granted.
-S [pathname]: True if pathname resolves to an existing directory entry for a socket. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that is not a socket.
-s [pathname]: True if pathname resolves to an existing directory entry for a file that has a size greater than zero. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that does not have a size greater than zero.
-u [pathname]: True if pathname resolves to an existing directory entry for a file that has its set-user-ID flag set. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file that does not have its set-user-ID flag set.
-w [pathname]: True if pathname resolves to an existing directory entry for a file for which permission to write to the file will be granted, as defined in File Read, Write, and Creation. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file for which permission to write to the file will not be granted.
-x [pathname]: True if pathname resolves to an existing directory entry for a file for which permission to execute the file (or search it, if it is a directory) will be granted, as defined in File Read, Write, and Creation. False if pathname cannot be resolved, or if pathname resolves to an existing directory entry for a file for which permission to execute (or search) the file will not be granted.
-z [string]: True if the length of string string is zero; otherwise, false.
s1 = s2: True if the strings s1 and s2 are identical; otherwise, false.
s1 != s2: True if the strings s1 and s2 are not identical; otherwise, false.
n1 -eq n2: True if the integers n1 and n2 are algebraically equal; otherwise, false.
n1 -ne n2: True if the integers n1 and n2 are not algebraically equal; otherwise, false.
n1 -gt n2: True if the integer n1 is algebraically greater than the integer n2; otherwise, false.
n1 -ge n2: True if the integer n1 is algebraically greater than or equal to the integer n2; otherwise, false.
n1 -lt n2: True if the integer n1 is algebraically less than the integer n2; otherwise, false.
n1 -le n2: True if the integer n1 is algebraically less than or equal to the integer n2; otherwise, false.
! [expression]: True if expression is false. False if expression is true.
3.1.15 true
Does nothing except return an exit status of 0, meaning "success".
3.1.16 type
Describe a command. For each name, indicate how it would be interpreted if used as a command name.
3.1.17 unalias
Remove each name from the list of aliases.
3.1.17.1 Options
-a: all aliases are removed.
3.1.18 unset
Remove variable.
3.1.19 fc
Process the command history list.
3.1.19.1 Options
-e [editor]: Use the editor named by editor to edit the commands. The editor string is a utility name, subject to search via the PATH variable. The value in the FCEDIT variable shall be used as a default when -e is not specified. If FCEDIT is null or unset, ed shall be used as the editor.
-l: List the commands rather than invoking an editor on them. The commands shall be written in the sequence indicated by the first and last operands, as affected by -r, with each command preceded by the command number.
-n: Suppress command numbers when listing with -l.
-r: Reverse the order of the commands listed (with -l) or edited (with neither -l nor -s).
-s: Re-execute the command without invoking an editor.