writing script with using sudo nano inside it

[monapi]

hello, i'm trying to write a shell script for turning raspi to an access point. is there someone who know how can i use "sudo nano" command to make a new file or edit a file in side a shell script and write and put some data into it and save and close it and go no another command in the script?
thanks.

[RaTTuS]

don't , use sed instead https://www.gnu.org/software/sed/manual/sed.html

[jahboater]

+1, sed is designed for the purpose.

Also, you can use the shell for simple things:-

To make a new file (easiest way):

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cat <<EOF >myfile
text line 1
text line 2
text line 3
EOF

To create a single line file:

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echo "line of text" >myfile

To add a line to the end of a file called "myfile":

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echo "Extra line of text" >>myfile

The same applies to "shar" files:

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cat <<EOF >>myfile 
text line 1
text line 2
text line 3
EOF

appends a block of text to file.

[monapi]

how can i write

To configure the static IP address, edit the dhcpcd configuration file with:

sudo nano /etc/dhcpcd.conf
Go to the end of the file and edit it so that it looks like the following:

interface wlan0
static ip_address=192.168.4.1/24
nohook wpa_supplicant
Now restart the dhcpcd daemon and set up the new wlan0 configuration:

sudo service dhcpcd restart

in the shell script?
i try writing

echo "interface wlan0
static ip_address=192.168.5.5/24
nohook wpa_supplicant" >> /etc/dhcpcd.conf
sudo service dhcpcd restart

but i see

/etc/dhcpcd.conf: Permission denied

error. how should i use sed to solve it?

[jahboater]

Prefix the command with sudo.
This system config file requires admin permission to alter it.

Also although your echo command does work for a multiple line file in bash, the more common way is the "shar" method.

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sudo cat <<EOF >>/etc/dhcpcd.conf
interface wlan0
static ip_address=192.168.5.5/24
nohook wpa_supplicant
EOF

[monapi]

Prefix the command with sudo.
This system config file requires admin permission to alter it.

Also although your echo command does work for a multiple line file in bash, the more common way is the "shar" method.

Code: Select all

sudo cat <<EOF >>/etc/dhcpcd.conf
interface wlan0
static ip_address=192.168.5.5/24
nohook wpa_supplicant
EOF

thank you
i use code but it give the same error and add sudo for my code and it didn't help.
what is wrong?

[Paeryn]

Prefix the command with sudo.
This system config file requires admin permission to alter it.

Also although your echo command does work for a multiple line file in bash, the more common way is the "shar" method.

Code: Select all

sudo cat <<EOF >>/etc/dhcpcd.conf
interface wlan0
static ip_address=192.168.5.5/24
nohook wpa_supplicant
EOF

Running cat with sudo like that won't solve the permission problem, the file redirection is handled by the shell and isn't affected by sudo. You need to tell sudo to run a shell which runs the command.

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sudo /bin/sh -c "cat <<EOF >>/etc/dhcpcd.conf
interface wlan0
static ip_address=192.168.5.5/24
nohook wpa_supplicant
EOF"

[jahboater]

Running cat with sudo like that won't solve the permission problem, the file redirection is handled by the shell and isn't affected by sudo. You need to tell sudo to run a shell which runs the command.

Yes, thats what I thought - but strangely it does work.
Seems user Pi is in the same group (netdev), and group write is enabled.

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pi@Pi3:~ $ id
uid=1000(pi) gid=1000(pi) groups=1000(pi),4(adm),20(dialout),24(cdrom),27(sudo),29(audio),44(video),46(plugdev),60(games),100(users),101(input),108(netdev),997(gpio),998(i2c),999(spi)
pi@Pi3:~ $ ls -l /etc/dhcpcd.conf
-rw-rw-r-- 1 root netdev 1842 Aug 28 14:30 /etc/dhcpcd.conf
pi@Pi3:~ $ 

There is no permission problem for user pi.

[mfa298]

Yes, thats what I thought - but strangely it does work.
Seems user Pi is in the same group (netdev), and group write is enabled.

In that case sudo isn't needed at all.

Running cat with sudo like that won't solve the permission problem, the file redirection is handled by the shell and isn't affected by sudo. You need to tell sudo to run a shell which runs the command.

Alternatively use tee

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sudo tee -a /etc/dhcpcd.conf <<EOF
interface wlan0
static ip_address=192.168.5.5/24
nohook wpa_supplicant
EOF

(you may also want a > /dev/null in there otherwise tee will output what it's written to the file as well as writing it)

[monapi]

hello,
how can i write an script for thes lines?
these are for making acess point from a raspberry pi and really hard to write.
i don't know how to add lines to an specific part of a file or uncomment a line with script.

Find the line with #DAEMON_CONF, and replace it with this:

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DAEMON_CONF="/etc/hostapd/hostapd.conf"

and

Edit /etc/sysctl.conf and uncomment this line:

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net.ipv4.ip_forward=1

and

Add a masquerade for outbound traffic on eth0:

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sudo iptables -t nat -A  POSTROUTING -o eth0 -j MASQUERADE

Save the iptables rule.

and

Edit /etc/rc.local and add this just above "exit 0" to install these rules on boot.

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iptables-restore < /etc/iptables.ipv4.nat

thanks for helping me.

[RaTTuS]

see sed

[Ernst]

see sed

you beat me

[B.Goode]

see sed

you beat me

Trouble is, that was the advice given in the first two replies to this thread. And that was over a week ago...

In the absence of an offer to write the entire solution, perhaps a little example would be useful? (I've never been fluent in sed, but I know it has been part of the Unix programming environment since forever. Deliberate reference there to a book which contains relevant documentation... )

[RaTTuS]

well - rather than do exaples check out
https://linuxconfig.org/learning-linux-commands-sed
it will help in the future

[Ernst]

In the absence of an offer to write the entire solution, perhaps a little example would be useful?

As an alternative a google search could help the op:
https://www.google.de/search?q=site%3Aw ... e&ie=UTF-8

[B.Goode]

perhaps a little example would be useful? (I've never been fluent in sed, but I know it has been part of the Unix programming environment since forever. Deliberate reference there to a book which contains relevant documentation... )

Sorry. Obviously way too obscure.

To be clear. This book, The Unix Programming Environment - Brian w. Kernighan Rob Pike , has a section of about 6 pages devoted to sed.

It can be read/downloaded here, amongst other places - https://www.scribd.com/doc/78859016/Uni ... n-Rob-Pike