extracting version string in shell script - linux

I've a progam installed in my linux box called my-scheduler-1.1.0-1112
When I do rpm -qa | grep my, it lists as shown below:
my-scheduler-1.1.0-1112
I want a command which will extract 1.1.0-1112 which is version part in my shell script.
what would be the command to extract it in shell script?

For this question you can try the --queryformat parameter for rpm.
like:
rpm -qa --queryformat '%{NAME}' | grep my
should print
my-scheduler
without the version string... What is much better as mugling it with sed or like. Because you can get something like package-1.0.3-rc2 or soo..
For version-release: use:
--queryformat "%{VERSION}-%{RELEASE}"
and maybe will be useful read http://www.rpm.org/max-rpm/ch-queryformat-tags.html - here is many useful query format tags, so you can directly can get what you want and in what format you want, without scripting...

Not sure what other version strings you may encounter, but you can try:
sed -e 's/^[^0-9]*-//g'
This is a sed replace. It's matching the regular expression ^[^0-9]*-, which is:
starting from the beginning of the String
match as many non-numbers as there are
then the very next character is a -
And it replaces everything that matched with a blank, essentially removing it. This should leave everything after that which is the version string.

Related

How to read a variable from file, modify and safe it to an other variale

What I want:
There is a file /scripts/backup/config.cfg which contains variables. In my specific case the important ones are:
BACKUPLOCATION=""
ROOTLOCATION="/backup"
Then there is a script /scripts/backup/performBackup.sh
For a specific reason I want a part of the script do the following operations:
read the value of the variable ROOTLOCATION
add a ("/" and) timestamp (Date&Time)
safe the new created value to BACKUPLOCATION (by replacing its current value)
Example
If this is the previous state of the config.cfg:
BACKUPLOCATION="dummy"
ROOTLOCATION="/backup"
After the script ran it should be:
BACKUPLOCATION="/backup/2020-05-02-23-00"
ROOTLOCATION="/backup/"
What I tried
First of all the config file gets "loaded" using
source /scripts/backup/config.cfg
I then tried to use the sed command but the quotes are messing with me. Here is one try (which didn't work):
sed -i 's/BACKUPLOCATION\=.*/BACKUPLOCATION="'$ROOTLOCATION/$(date +%Y-%m-%d-%H-%M)'"/' /scripts/backup/config.cfg
Try this:
source /scripts/backup/config.cfg
sed -i 's|BACKUPLOCATION=.*|BACKUPLOCATION="'"$ROOTLOCATION/$(date +%Y-%m-%d-%H-%M)"'"|' /scripts/backup/config.cfg
The problem with your sed is that you use / as delimiter, which is present in $ROOTLOCATION after expansion, therefore sed fails. I used |, which is usually is not present in filenames. If you ever create a file with |, that sed will fail too! So, "know your data" :)

how to use delimiter in the script to avoid numerical and special characters

Is there any logic to write a shell script to go back up into the previous directory which has "n" number of files like abc-1.0.1-xy.rpm, xyz-3.2.1-bc.rpm, a-bd-2.3.1-ty.rpm etc.. with same pattern.
I need the first name of it before the numeric starts(which can acts as a delimiter) i.e(-(0-9)) can be the delimiter. the output should be abc, xfz, a-bd, etc.
for p in *.rpm; do echo "${p%-*}"; done
I made a try with this command, but it stops and output as xyz-3.2.1. but I need xyz only.
If you need the package name of a rpm, use:
rpm -qp --queryformat '%{NAME}\n' *.rpm 2>/dev/null

Understanding sed

I am trying to understand how
sed 's/\^\[/\o33/g;s/\[1G\[/\[27G\[/' /var/log/boot
worked and what the pieces mean. The man page I read just confused me more and I tried the info sai Id but had no idea how to work it! I'm pretty new to Linux. Debian is my first distro but seemed like a rather logical place to start as it is a root of many others and has been around a while so probably is doing stuff well and fairly standardized. I am running Wheezy 64 bit as fyi if needed.
The sed command is a stream editor, reading its file (or STDIN) for input, applying commands to the input, and presenting the results (if any) to the output (STDOUT).
The general syntax for sed is
sed [OPTIONS] COMMAND FILE
In the shell command you gave:
sed 's/\^\[/\o33/g;s/\[1G\[/\[27G\[/' /var/log/boot
the sed command is s/\^\[/\o33/g;s/\[1G\[/\[27G\[/' and /var/log/boot is the file.
The given sed command is actually two separate commands:
s/\^\[/\o33/g
s/\[1G\[/\[27G\[/
The intent of #1, the s (substitute) command, is to replace all occurrences of '^[' with an octal value of 033 (the ESC character). However, there is a mistake in this sed command. The proper bash syntax for an escaped octal code is \nnn, so the proper way for this sed command to have been written is:
s/\^\[/\033/g
Notice the trailing g after the replacement string? It means to perform a global replacement; without it, only the first occurrence would be changed.
The purpose of #2 is to replace all occurrences of the string \[1G\[ with \[27G\[. However, this command also has a mistake: a trailing g is needed to cause a global replacement. So, this second command needs to be written like this:
s/\[1G\[/\[27G\[/g
Finally, putting all this together, the two sed commands are applied across the contents of the /var/log/boot file, where the output has had all occurrences of ^[ converted into \033, and the strings \[1G\[ have been converted to \[27G\[.

replace a line in linux file containing special characters

Here is an extract from a script showing the variables for the script
PathToPiconPNG="/var/OscamSrvidPicon/picon/19.2E/"
PathToOscamSrvid="/var/OscamSrvidPicon/picon/19.2E/oscam.srvid"
PathToPiconTPL="/var/OscamSrvidPicon/oscam_picons/"
PathToTmp="/tmp/"
I want to run this script numerous times replacing (for example) this line:
PathToPiconPNG="/var/OscamSrvidPicon/picon/19.2E/"
with this lines
PathToPiconPNG="/var/OscamSrvidPicon/picon/28.2E/"
I have tried using sed (I know this example is wrong but you might get what im trying to achieve)
sed 's/{PathToPiconPNG="/var/OscamSrvidPicon/picon/19.2E/"}/{PathToPiconPNG="/var/OscamSrvidPicon/picon/28.2E/"}/g' filename.txt > newfilenam.txt
If that is not possible, is there any way that I can set the variable externally from another script
sed -E 's/picon\/.+\//picon\/28.2E\//' filename.txt > newfilenam.txt

Using wildcards to exclude files with a certain suffix

I am experimenting with wildcards in bash and tried to list all the files that start with "xyz" but does not end with ".TXT" but getting incorrect results.
Here is the command that I tried:
$ ls -l xyz*[!\.TXT]
It is not listing the files with names "xyz" and "xyzTXT" that I have in my directory. However, it lists "xyz1", "xyz123".
It seems like adding [!\.TXT] after "xyz*" made the shell look for something that start with "xyz" and has at least one character after it.
Any ideas why it is happening and how to correct this command? I know it can be achieved using other commands but I am especially interested in knowing why it is failing and if it can done just using wildcards.
These commands will do what you want
shopt -s extglob
ls -l xyz!(*.TXT)
shopt -u extglob
The reason why your command doesn't work is beacause xyz*[!\.TXT] which is equivalent to xyz*[!\.TX] means xyz followed by any sequence of character (*) and finally a character in set {!,\,.,T,X} so matches 'xyzwhateveryouwant!' 'xyzwhateveryouwant\' 'xyzwhateveryouwant.' 'xyzwhateveryouwantT' 'xyzwhateveryouwantX'
EDIT: where whateveryouwant does not contain any of !\.TX
I don't think this is doable with only wildcards.
Your command isn't working because it means:
Match everything that has xyz followed by whatever you want and it must not end with sequent character: \, .,T and X. The second T doesn't count as far as what you have inside [] is read as a family of character and not as a string as you thought.
You don't either need to 'escape' . as long as it has no special meaning inside a wildcard.
At least, this is my knowledge of wildcards.

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