This question already has answers here:
How to concatenate string variables in Bash
(30 answers)
Closed 1 year ago.
So I'm trying to compose a string using script shell
#!/bin/sh
blNumber=1111619832
echo '*'$blNumber+='*.xlsx'
I expect the output to be: *1111619832*.xlsx
but as a result I get: *+=*.xlsx
Btw I tried to figure out why so I tried this code
#!/bin/sh
blNumber=1111619832
output="*${blNumber}"
and whenever I add something after *${blNumber} it get concatenated at the begging of the string
Why are you using += in the first place?
$ echo '*'$blNumber'*.xlsx'
*1111619832*.xlsx
Or put it inside double-quotes. It's best practice to quote all variables anyway.
$ echo "*$blNumber*.xlsx"
*1111619832*.xlsx
Related
This question already has answers here:
How to execute a bash command stored as a string with quotes and asterisk [duplicate]
(5 answers)
Closed 2 years ago.
I want to compose a command in a shell script like this:
#!/bin/sh
APPLICATION="date"
PARAMETER="-d '2020-01-01 1:23'"
CMD="${APPLICATION} ${PARAMETER}"
${CMD}
The 'PARAMETER' is supposed to hold parameters that need to be quoted themself. Unfortunately it does not work like this. Escaping them via PARAMETER="-d \"2020-01-01 1:23\"" also does not work.
After you've build CMD up, it is just string. It contains what can be interpreted by you as a command, but the shell sees it as a bare string.
If you want the string to reinterpret it, you need to eval it:
eval "$CMD"
However, eval is often considered evil.
This question already has answers here:
How to execute a bash command stored as a string with quotes and asterisk [duplicate]
(5 answers)
Command not found error in Bash variable assignment
(5 answers)
Closed 4 years ago.
I have an application in Unix. I use the below command to connect to it:
./application -a "connect"
I want to do the same through the shell script, for which i assigned the command line to a variable like:
newcommand = './application -a "connect"'
$newcommand
But this is not working.
However the first part of the code is working. i.e.,:
newcommand = "./application"
$newcommand
Can anyone point out what i am missing.
Believe it or not, this:
newcommand = "./application"
...has the shell run the command, newcommand with the arguments, =, and ./application.
In shell simple assignments cannot have any unprotected whitespace or they'll be interpreted as a command.
Consider:
newcommand=./application
$newcommand
...notice that there's no space around the = sign in the assignment.
This question already has answers here:
How can I remove the extension of a filename in a shell script?
(15 answers)
Closed 5 years ago.
I have hundreds files need to loop through for an analysis using a bash script. One step I need to do is to split a long string and cat it as an output name. For example, suppose I have one string such like:
5018.a.Radiation_Induced_Lymphoma.Tumor__p53+_-.SL200300_SL200300.exome_1tier.mm10.kapa_re_cap_v6_3utr.final.bam
What I wanted is to rename it as two output file names such as:
5018.a.Radiation_Induced_Lymphoma.Tumor__p53+_-.SL200300_SL200300.exome_1tier.mm10.kapa_re_cap_v6_3utr.final_R1.fastq
5018.a.Radiation_Induced_Lymphoma.Tumor__p53+_-.SL200300_SL200300.exome_1tier.mm10.kapa_re_cap_v6_3utr.final_R2.fastq
The only changes are removing .bam from the original and cat _R1.fastq and _R2_fastq. Does somebody know how to realize it using bash commands?
somefile=blahblahblah.final.bam
foo "$somefile" "${somefile%.*}_R1.fastq" "${somefile%.*}_R2.fastq"
This question already has answers here:
Script parameters in Bash
(5 answers)
Closed 6 years ago.
I've written a simple bash script, named ocropus:
#!/bin/bash
read filename path
...
And then i realized that I can't run it like this:
ocropus filename path
Instead, I need to run it like this:
ocropus
filename path
What can I do so I don't need to hit enter before my inputs? Thanks a lot!
Command line arguments are in $1, $2, etc. So do:
filename=$1
path=$2
instead of
read filename path
This question already has answers here:
Shell command to retrieve specific value using pattern
(3 answers)
Closed 8 years ago.
I have file test.txt contains the following
AA=testing
BB=help
CC=hello
How can i make a bash script that will get each value and assign to a new variable?
#!/bin/bash
var1=testing
var2=help
var3=hello
thanks for the help
First of all a = value is not correct syntax in shell. In shell the spaces are important.
When you have a valid file, you can use the eval function to evaluate that file as a string, or simply source it.