I have a bash string variable:
switches="-r cc -c 1,2,3,4 -u"
where numbers 1,2,3,4 can be any integer, like:
-c 25,45,78,34.
Moreover, it can be with fewer numbers, like:
-c 1
-c 1,2
or
-c 1,2,3,4
It can't be like:
-c 1,2,3
So -c can have one, two, or four integers only.
I forgot to mention that that this pattern can appeares also at the beginning, or at the end of the string variable $switches too, like:
-r cc -u -c 1,2,3,4
-r cc -u -c 1,2,3
And one more thing: this pattern can be appeared in the $switches variable only once.
How can I remove the '-c 1,2,3,4 ' part of switches variable using just bash?
I tried with this:
switches=${switches/ -c /}
but get this:
-r cc1,2,3,4 -u
I expect this:
-r cc -u
Best, Pal
Using extglob:
shopt -s extglob # enables extended globbing
switches=${switches//-c *([^ ])}
*([^ ]): matches any number of non-spaces
This will leave you with unnecessary spaces. More complicated solution:
switches=${switches//-c *([^ ])*( )}
switches=${switches/%*( )}
*([^ ])*( ): matches any number of non-spaces and any number of spaces after
${switches/%*( )}: if the last option is also -c, the code above wouldn't remove the spaces left by it. /%*( ) removes any number of spaces from the end
Related
Basically what foo(**bar) does in python, here I’d want something like
foo **bar.yaml
and that would become
foo --bar1=1 --bar2=2
Where bar.yaml would be
bar1: 1
bar2: 2
You could use a combination of sed and xargs:
sed -E 's/^(.+):[[:space:]]+(.+)$/--\1=\2/' bar.yaml | xargs -d '\n' foo
sed converts the format of bar.yaml lines (e.g. bar1: 1 -> --bar1=1) and xargs feeds the converted lines as arguments to foo.
You could of course modify/extend the sed part to support other formats or single-dash options like -v.
To test if this does what you want, you can run this Bash script instead of foo:
#!/usr/bin/env bash
echo "Arguments: $#"
for ((i=1; i <= $#; i++)); do
echo "Argument $i: '${!i}'"
done
Here's a version for zsh. Run this code or add it to ~/.zshrc:
function _yamlExpand {
setopt local_options extended_glob
# 'words' array contains the current command line
# yaml filename is the last value
yamlFile=${words[-1]}
# parse 'key : value' lines from file, create associative array
typeset -A parms=("${(#s.:.)${(f)"$(<${yamlFile})"}}")
# trim leading and trailing whitespace from keys and values
# requires extended_glob
parms=("${(kv#)${(kv#)parms##[[:space:]]##}%%[[:space:]]##}")
# add -- and = to create flags
typeset -a flags
for key val in "${(#kv)parms}"; do
flags+=("--${key}='${val}'")
done
# replace the value on the command line
compadd -QU -- "$flags"
}
# add the function as a completion and map it to ctrl-y
compdef -k _yamlExpand expand-or-complete '^Y'
At the zsh shell prompt, type in the command and the yaml file name:
% print -l -- ./bar.yaml▃
With the cursor immediately after the yaml file name, hit ctrl+y. The yaml filename will be replaced with the expanded parameters:
% print -l -- --bar1='1' --bar2='2' ▃
Now you're set; you can hit enter, or add parameters, just like any other command line.
Notes:
This only supports the yaml subset in your example.
You can add more yaml parsing to the function, possibly with yq.
In this version, the cursor must be next to the yaml filename - otherwise the last value in words will be empty. You can add code to detect that case and then alter the words array with compset -n.
compadd and compset are described in the zshcompwid man page.
zshcompsys has details on compdef; the section on autoloaded files describes another way to deploy something like this.
I have this command:
num_lines="$(wc -l "$HOME/my_bash_history")"
Which yields:
17 /Users/alex/my_bash_history
So I tried to get the first token using:
local read num_lines < <(wc -l "$HOME/my_bash_history")
But all I get is empty result:
num lines:
Anybody know why?
wc reports the file name unless it is reading from stdin. So, keep it simple, just use:
$ num_lines="$(wc -l <"$HOME/my_bash_history")"
$ echo "$num_lines"
17
If you really want to use read with process substitution, then use two arguments to read like this:
$ read num_lines fname < <(wc -l "$HOME/my_bash_history")
$ echo "$num_lines"
17
or, use a here-string like this:
$ read num_lines fname <<<"$(wc -l "$HOME/my_bash_history")"
$ echo "$num_lines"
17
When read reads a line, the shell first splits the lines into words. The words are assigned to each argument in turn with the last argument receiving whatever remains. In our case, this means the the number is assigned to num_lines and whatever words follow the number are assigned to fname.
try this:
num_lines="$(wc -l $HOME/my_bash_history)"
echo "${num_lines%% *}"
explanation
${num_lines%% *} # delete all after first blank
I'm writing a for loop in bash to run a command and I need to add a comma after one of my variables. I can't seem to do this without an extra space added. When I move "," right next to $bams then it outputs *.sorted,
#!/bin/bash
bams=*.sorted
for i in $bams
do echo $bams ","
done;
Output should be this:
'file1.sorted','file2.sorted','file3.sorted'
The eventual end goal is to be able to insert a list of files into a --flag in the format above. Not sure how to do that either.
First, a literal answer (if your goal were to generate a string of the form 'foo','bar','baz', rather than to run a program with a command line equivalent to somecommand --flag='foo','bar','baz', which is quite different):
shopt -s nullglob # generate a null result if no matches exist
printf -v var "'%s'," *.sorted # put list of files, each w/ a comma, in var
echo "${var%,}" # echo contents of var, with last comma removed
Or, if you don't need the literal single quotes (and if you're passing your result to another program on its command line with the single quotes being syntactic rather than literal, you absolutely don't want them):
files=( *.sorted ) # put *.sorted in an array
IFS=, # set the comma character as the field separator
somecommand --flag "${files[*]}" # run your program with the comma-separated list
try this -
lst=$( echo *.sorted | sed 's/ /,/g' ) # stack filenames with commas
echo $lst
if you really need the single-ticks around each filename, then
lst="'$( echo *.sorted | sed "s/ /','/g" )'" # commas AND quotes
#!/bin/bash
bams=*.sorted
for i in $bams
do flag+="${flag:+,}'$i'"
done
echo $flag
I have a variable equal to a string, which is a series of key/value pairs separated by newlines.
I want to then replace these newline characters with spaces, and set a new variable equal to the result
From various answers on the internet I've arrived at the following:
#test.txt has the content:
#test=example
#what=s0omething
vars="$(cat ./test.txt)"
formattedVars= $("$vars" | tr '\n' ' ')
echo "$taliskerEnvVars"
Problem is when I try to set formattedVars it tries to execute the second line:
script.sh: line 7: test=example
what=s0omething: command not found
I just want formattedVars to equal test=example what=s0omething
What trick am I missing?
Change your line to:
formattedVars=$(tr '\n' ' ' <<< "$secretsContent")
Notice the space of = in your code, which is not permitted in assignment statements.
I see that you are not setting secretsContent in your code, you are setting vars instead.
If possible, use an array to hold contents of the file:
readarray -t vars < ./test.txt # bash 4
or
# bash 3.x
declare -a vars
while IFS= read -r line; do
vars+=( "$line" )
done < ./test.txt
Then you can do what you need with the array. You can make your space-separated list with
formattedVars="${vars[*]}"
, but consider whether you need to. If the goal is to use them as a pre-command modifier, use, for instance,
"${vars[#]}" my_command arg1 arg2
I have a script that exports a XML file to my desktop and then extracts all the data in the "id" tags and exports that to a csv file.
xmlstarlet sel -t -m '//id[1]' -v . -n </users/$USER/Desktop/List.xml > /users/$USER/Desktop/List2.csv
I then use the following command to add commas after each number and store it as a variable.
devices=$(sed "s/$/,/g" /users/$USER/Desktop/List2.csv)
If I echo that variable I get an output that looks like this:
123,
124,
125,
etc.
What I need help with is removing those spaces so that output will look like 123,124,125 with no leading space. I've tried multiple solutions that I can't get to work. Any help would be amazing!
If you don't want newlines, don't tell xmlstarlet to put them there in the first place.
That is, change -n to -o , to put a comma after each value rather than a newline:
{ xmlstarlet sel -t -m '//id[1]' -v . -o ',' && printf '\n'; } \
<"/users/$USER/Desktop/List.xml" \
>"/users/$USER/Desktop/List2.csv"
The printf '\n' here puts a final newline at the end of your CSV file after xmlstarlet has finished writing its output.
If you don't want the trailing , this leaves on the output file, the easiest way to be rid of it is to read the result of xmlstarlet into a variable and manipulate it there:
content=$(xmlstarlet sel -t -m '//id[1]' -v . -o ',' <"/users/$USER/Desktop/List.xml")
printf '%s\n' "${content%,}" >"/users/$USER/Desktop/List2.csv"
For a sed solution, try
sed ':a;N;$!ba;y/\n/,/' /users/$USER/Desktop/List2.csv
or if you want a comma even after the last:
sed ':a;N;$!ba;y/\n/,/;s/$/,/' /users/$USER/Desktop/List2.csv
but then more easy would be
cat /users/$USER/Desktop/List2.csv | tr "\n" ","