mkinitrd-6_1_12/nash/nash.8

.TH NASH 8 "Mon Aug 02 2004"
.SH NAME
nash \- script interpretor to interpret linuxrc images
.SH SYNOPSIS
\fBnash\fR [--quiet] [--force] \fIscript\fR

.SH DESCRIPTION
\fBnash\fR is a very simple script interpretor designed to be as small as
possible. It is primarily designed to run simple linuxrc scripts on an initrd
image. Arguments to commands may be enclosed in either single or double
quotes to allow spaces to be included in the arguments. Spaces outside of
quotations always delineate arguments, and so backslash escaping is supported.

Additionally, if nash is invoked as \fBmodprobe\fR, it will immediately
exit with a return code of zero. This is to allow initrd's to prevent some
extraneous kernel error messages during startup.

There are two types of commands, built in and external. External commands
are run from the filesystem via execve(). If commands names are given without
a path, nash will search it's builtin PATH, which is /usr/bin, /bin,
/sbin, /usr/sbin.

Currently, \fBnash\fR supports the following built in commands.

.TP
\fBaccess -[r][w][x][f] \fIpath\fR
Tells whether the current user has sufficient permissions to read, write, or
execture \fIpath\fR, or if the file exists (see \fBaccess(2)\fR for more
information).

.TP
\fBecho [item]* [> \fIfilename\fR]\fR
Echos the text strings given to a file, with a space in between each
item. The output may be optionally redirected to a file.

\fBexec\fR \fI<command>\fR
The command given is execed, overlaying the nash process.

.TP
\fBfind \fIdir\fR -name \fIname\fR
Display the path to files named \fIname\fR in or below directory \fIdir\FR.
This is a \fBvery\fR limited implementation of find(1).

.TP
\fBfindlodev\fR
Prints the full path to the first unused loopback block device on the
system. If none is available, no output is displayed.

.TP
\fBlosetup \fI/dev/loopdev\fR \fIfile\fR
Binds \fIfile\fR to the loopback device \fI/dev/loopdev\fR. See
\fBlosetup(8)\fR for information on loopback devices.

.TP
\fBmkdevices\fR \fIpath\fR
Creates device files for all of the block devices listed in 
\fB/proc/partitions\fR in the directory specfied by \fIpath\fR.

.TP
\fBmkdir\fR \fI[-p]\fR \fIpath\fR
Creates the directory \fIpath\fR. If \fI-p\fR is specified, this command
will not complain if the directory exists. Note this is a subset of the
standard \fBmkdir\fR \fI-p\fR behavior.

.TP
\fBmknod\fR \fIpath\fR \fI[c|b]\fR \fImajor\fR \fIminor\fR 
Creates a device inode for \fIpath\fR. This is identical to \fBmkdev\fR(1)
which the exceptions that it will not create named pipes and if the directories
in \fIpath\fR do not exist they will be automatically created.

.TP
\fBmkdmnod\fR
Creates a device inode for the device mapper control inode as
\fI/dev/mapper/control\fR.  If it already exists with the correct
major/minor, it will not be recreated.

.TP
\fBmkrootdev \fIpath\fR
Makes \fIpath\fR a block inode for the device which should be mounted
as root. To determine this device nash uses 
the device suggested by the root= kernel command line argument (if
root=LABEL is used devices are probed to find one with that label). If
no root= argument is available, /proc/sys/kernel/real-root-dev provides
the device number.

.TP
\fBmount \fI[--ro]\fR -o \fIopts\fR -t \fItype\fR \fIdevice\fR \fImntpoint\fR
Mounts a filesystem. It does not support NFS, and it must be used in
the form given above (arguments must go first).  If \fIdevice\fR is of the form
\fBLABEL=\fIfoo\fR the devices listed in /fB/proc/partitions\fR will
be searched, and the first device with a volume label of \fIfoo\fR will
be mounted. Normal \fBmount\fR(2) options are supported, and \fB--ro\fR will
mount the filesystem read only for compatibility with older versions of nash.
The \fBdefaults\fR mount option is silently ignored.

.TP
\fBpivot_root \fInewrootpath\fR \fIoldrootpath\fR
Makes the filesystem mounted at \fInewrootpath\fR the new root filesystem,
and mounts the current root filesystem as \fIoldrootpath\fR.

.TP
\fBreadlink \fIpath\fR
Displays the value of the symbolic link \fIpath\fR.

.TP
\fBraidautorun \fImddevice\fR
Runs raid autodetection on all raid-typed partitions. \fImddevice\fR must
be a raid device (any will do).

.TP
\fBsetquiet\fR
Cause any later echos in this script to not be displayed.

.TP
\fBshowlabels\fR
Display a table of devices, their filesystem labels, and their uuids.

.TP
\fBsleep \fInum\fR
Sleep for \fInum\fR seconds

.TP
\fBswitchroot \fInewrootpath\fR
Makes the filesystem mounted at \fInewrootpath\fR the new root
filesystem by moving the mountpoint.  This will only work in 2.6 or
later kernels.

.TP
\fBumount \fIpath\fR
Unmounts the filesystem mounted at \fIpath\fR.

.SH RETURN VALUE
Returns 0 is the last command succeeded or 1 if it failed.

.SH OPTIONS
.TP
\fB-\-force\fR
Allows \fBforce\fR really execute the script, even though \fBnash\fR doesn't 
appear to be running from an initrd image.

.SH BUGS
Probably many. \fBnash\fR is \fbnot a shell\fR, and it shouldn't be thought of
as one. It isn't entirely different from a shell, but that's mostly by
accident.

.SH AUTHOR
.nf
Erik Troan <ewt@redhat.com>
.fi
1	niro	532	.TH NASH 8 "Mon Aug 02 2004"
2			.SH NAME
3			nash \- script interpretor to interpret linuxrc images
4			.SH SYNOPSIS
5			\fBnash\fR [--quiet] [--force] \fIscript\fR
6
7			.SH DESCRIPTION
8			\fBnash\fR is a very simple script interpretor designed to be as small as
9			possible. It is primarily designed to run simple linuxrc scripts on an initrd
10			image. Arguments to commands may be enclosed in either single or double
11			quotes to allow spaces to be included in the arguments. Spaces outside of
12			quotations always delineate arguments, and so backslash escaping is supported.
13
14			Additionally, if nash is invoked as \fBmodprobe\fR, it will immediately
15			exit with a return code of zero. This is to allow initrd's to prevent some
16			extraneous kernel error messages during startup.
17
18			There are two types of commands, built in and external. External commands
19			are run from the filesystem via execve(). If commands names are given without
20			a path, nash will search it's builtin PATH, which is /usr/bin, /bin,
21			/sbin, /usr/sbin.
22
23			Currently, \fBnash\fR supports the following built in commands.
24
25			.TP
26			\fBaccess -[r][w][x][f] \fIpath\fR
27			Tells whether the current user has sufficient permissions to read, write, or
28			execture \fIpath\fR, or if the file exists (see \fBaccess(2)\fR for more
29			information).
30
31			.TP
32			\fBecho [item]* [> \fIfilename\fR]\fR
33			Echos the text strings given to a file, with a space in between each
34			item. The output may be optionally redirected to a file.
35
36			\fBexec\fR \fI<command>\fR
37			The command given is execed, overlaying the nash process.
38
39			.TP
40			\fBfind \fIdir\fR -name \fIname\fR
41			Display the path to files named \fIname\fR in or below directory \fIdir\FR.
42			This is a \fBvery\fR limited implementation of find(1).
43
44			.TP
45			\fBfindlodev\fR
46			Prints the full path to the first unused loopback block device on the
47			system. If none is available, no output is displayed.
48
49			.TP
50			\fBlosetup \fI/dev/loopdev\fR \fIfile\fR
51			Binds \fIfile\fR to the loopback device \fI/dev/loopdev\fR. See
52			\fBlosetup(8)\fR for information on loopback devices.
53
54			.TP
55			\fBmkdevices\fR \fIpath\fR
56			Creates device files for all of the block devices listed in
57			\fB/proc/partitions\fR in the directory specfied by \fIpath\fR.
58
59			.TP
60			\fBmkdir\fR \fI[-p]\fR \fIpath\fR
61			Creates the directory \fIpath\fR. If \fI-p\fR is specified, this command
62			will not complain if the directory exists. Note this is a subset of the
63			standard \fBmkdir\fR \fI-p\fR behavior.
64
65			.TP
66			\fBmknod\fR \fIpath\fR \fI[c\|b]\fR \fImajor\fR \fIminor\fR
67			Creates a device inode for \fIpath\fR. This is identical to \fBmkdev\fR(1)
68			which the exceptions that it will not create named pipes and if the directories
69			in \fIpath\fR do not exist they will be automatically created.
70
71			.TP
72			\fBmkdmnod\fR
73			Creates a device inode for the device mapper control inode as
74			\fI/dev/mapper/control\fR. If it already exists with the correct
75			major/minor, it will not be recreated.
76
77			.TP
78			\fBmkrootdev \fIpath\fR
79			Makes \fIpath\fR a block inode for the device which should be mounted
80			as root. To determine this device nash uses
81			the device suggested by the root= kernel command line argument (if
82			root=LABEL is used devices are probed to find one with that label). If
83			no root= argument is available, /proc/sys/kernel/real-root-dev provides
84			the device number.
85
86			.TP
87			\fBmount \fI[--ro]\fR -o \fIopts\fR -t \fItype\fR \fIdevice\fR \fImntpoint\fR
88			Mounts a filesystem. It does not support NFS, and it must be used in
89			the form given above (arguments must go first). If \fIdevice\fR is of the form
90			\fBLABEL=\fIfoo\fR the devices listed in /fB/proc/partitions\fR will
91			be searched, and the first device with a volume label of \fIfoo\fR will
92			be mounted. Normal \fBmount\fR(2) options are supported, and \fB--ro\fR will
93			mount the filesystem read only for compatibility with older versions of nash.
94			The \fBdefaults\fR mount option is silently ignored.
95
96			.TP
97			\fBpivot_root \fInewrootpath\fR \fIoldrootpath\fR
98			Makes the filesystem mounted at \fInewrootpath\fR the new root filesystem,
99			and mounts the current root filesystem as \fIoldrootpath\fR.
100
101			.TP
102			\fBreadlink \fIpath\fR
103			Displays the value of the symbolic link \fIpath\fR.
104
105			.TP
106			\fBraidautorun \fImddevice\fR
107			Runs raid autodetection on all raid-typed partitions. \fImddevice\fR must
108			be a raid device (any will do).
109
110			.TP
111			\fBsetquiet\fR
112			Cause any later echos in this script to not be displayed.
113
114			.TP
115			\fBshowlabels\fR
116			Display a table of devices, their filesystem labels, and their uuids.
117
118			.TP
119			\fBsleep \fInum\fR
120			Sleep for \fInum\fR seconds
121
122			.TP
123			\fBswitchroot \fInewrootpath\fR
124			Makes the filesystem mounted at \fInewrootpath\fR the new root
125			filesystem by moving the mountpoint. This will only work in 2.6 or
126			later kernels.
127
128			.TP
129			\fBumount \fIpath\fR
130			Unmounts the filesystem mounted at \fIpath\fR.
131
132			.SH RETURN VALUE
133			Returns 0 is the last command succeeded or 1 if it failed.
134
135			.SH OPTIONS
136			.TP
137			\fB-\-force\fR
138			Allows \fBforce\fR really execute the script, even though \fBnash\fR doesn't
139			appear to be running from an initrd image.
140
141			.SH BUGS
142			Probably many. \fBnash\fR is \fbnot a shell\fR, and it shouldn't be thought of
143			as one. It isn't entirely different from a shell, but that's mostly by
144			accident.
145
146			.SH AUTHOR
147			.nf
148			Erik Troan <ewt@redhat.com>
149			.fi