Альтернативы для [переменная = подстановка строки] в bash

Я изучаю bash и пытаюсь понять различные способы выполнения подстановки и присвоения ее переменной .

В частности, я меняю косые черты Unix ('/') на Windows ('\').

Ссылки:

• https://stackoverflow.com/questions/20615217/bash-bad-substitution
• https://www.linode.com/docs/tools-reference/tools/manipulate-text- from-the-command-line-with-sed
• http://linuxpoison.blogspot.com/2012/06/bash-script-find-and-replace-string.html

С благодарностью Сету и Тердону .

Обновленная версия. Оригинал внизу.

#!/bin/bash
origPath="/home/django_auth_lifecycle/urls.py"

path=$origPath
path=${path//\//\\}                      #Works
echo "Via bash (2-slash, no-g): $path"

path=$origPath
path=${path//\//\\}                      #Works
echo "Via bash (no dollar): $path"

path=$origPath
echo "${path}" | sed -e 's/\//\\/g'     #Works, but don't know how to assign to var
#echo "Via sed (slash, quotes): $path"

path=$origPath
path=$(echo "$path" | sed s/'\/'/'\\'/g)   #Works
echo "Via sed (slash, quotes): $path"

path=$origPath
path=$(echo $path | sed s:'\/':'\\':g)   #Works
echo "Via sed (colon, quotes): $path"

path=$origPath                           #This and all following are
path=sed 's:/:\\:g' <<<$path             #s:/:\\:g: No such file or directory
echo "Via sed/<<< (colon): $path"

path=$origPath
path=sed 's/\//\\:g' <<<$path
echo "Via sed/<<< (slash): $path"

path=$origPath
path=sed 's/"\/"/"\\":g' <<<$path
echo "Via sed/<<< (slash, quotes): $path"

Вывод:

$ bash ./initial_script3.sh
Via bash (2-slash, no-g): \home\django_auth_lifecycle\urls.py
Via bash (no dollar): \home\django_auth_lifecycle\urls.py
./initial_script3.sh: line 13: ${echo "${path}" | sed -e 's/\//\\/g'}: bad substitution
Via sed (slash, quotes): /home/django_auth_lifecycle/urls.py
Via sed (slash, quotes): \home\django_auth_lifecycle\urls.py
Via sed (colon, quotes): \home\django_auth_lifecycle\urls.py
./initial_script3.sh: line 25: s:/:\\:g: No such file or directory
Via sed/<<< (colon): /home/django_auth_lifecycle/urls.py
./initial_script3.sh: line 29: s/\//\\:g: No such file or directory
Via sed/<<< (slash): /home/django_auth_lifecycle/urls.py
./initial_script3.sh: line 33: s/"\/"/"\\":g: No such file or directory
Via sed/<<< (slash, quotes): /home/django_auth_lifecycle/urls.py

Вывод с отладкой:

$ bash -x ./initial_script3.sh
+ origPath=/home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path='\home\django_auth_lifecycle\urls.py'
+ echo 'Via bash (2-slash, no-g): \home\django_auth_lifecycle\urls.py'
Via bash (2-slash, no-g): \home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path='\home\django_auth_lifecycle\urls.py'
+ echo 'Via bash (no dollar): \home\django_auth_lifecycle\urls.py'
Via bash (no dollar): \home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ sed -e 's/\//\\/g'
+ echo /home/django_auth_lifecycle/urls.py
\home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
++ sed 's/\//\\/g'
++ echo /home/django_auth_lifecycle/urls.py
+ path='\home\django_auth_lifecycle\urls.py'
+ echo 'Via sed (slash, quotes): \home\django_auth_lifecycle\urls.py'
Via sed (slash, quotes): \home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
++ sed 's:\/:\\:g'
++ echo /home/django_auth_lifecycle/urls.py
+ path='\home\django_auth_lifecycle\urls.py'
+ echo 'Via sed (colon, quotes): \home\django_auth_lifecycle\urls.py'
Via sed (colon, quotes): \home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path=sed
+ 's:/:\\:g'
./initial_script3.sh: line 25: s:/:\\:g: No such file or directory
+ echo 'Via sed/<<< (colon): /home/django_auth_lifecycle/urls.py'
Via sed/<<< (colon): /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path=sed
+ 's/\//\\:g'
./initial_script3.sh: line 29: s/\//\\:g: No such file or directory
+ echo 'Via sed/<<< (slash): /home/django_auth_lifecycle/urls.py'
Via sed/<<< (slash): /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path=sed
+ 's/"\/"/"\\":g'
./initial_script3.sh: line 33: s/"\/"/"\\":g: No such file or directory
+ echo 'Via sed/<<< (slash, quotes): /home/django_auth_lifecycle/urls.py'
Via sed/<<< (slash, quotes): /home/django_auth_lifecycle/urls.py

Исходный

Ниже показано то, что я пробовал. К сожалению, я могу заставить работать только один метод (sed с конвейером и , цитирующим каждый элемент). Первый работал, клянусь, а теперь нет.

Что я делаю не так?

#!/bin/bash
origPath="/home/django_auth_lifecycle/urls.py"

path=$origPath
path=${$path/\//\\/g}                    #WAS working, now not
echo "Via bash: $path"                   # ${$path/\//\\/g}: bad substitution

path=$origPath
path=${path/\//\\/g}                     #Bad output:
echo "Via bash (no dollar): $path"       #'\/ghome/django_auth_lifecycle/urls.py'

path=$origPath
path=$(echo $path | sed s/'\/'/'\\'/g)   #Works
echo "Via sed (slash, quotes): $path"

path=$origPath
#path=$(echo $path | sed s/\//\\/g)      #No error, but output=input
echo "Via sed (slash): $path"

path=$origPath
path=$(echo $path | sed s:'\/':'\\':g)   #Works
echo "Via sed (colon, quotes): $path"

path=$origPath
path=$(echo $path | sed s:\/:\\:g)       #sed: -e expression #1, char 7:
echo "Via sed (colon): $path"            #     unterminated `s' command

path=$origPath                           #This and all following are
path=sed 's:/:\\:g' <<<$path             #s:/:\\:g: No such file or directory
echo "Via sed/<<< (colon): $path"

path=$origPath
path=sed 's/\//\\:g' <<<$path
echo "Via sed/<<< (slash): $path"

path=$origPath
path=sed 's/"\/"/"\\":g' <<<$path
echo "Via sed/<<< (slash, quotes): $path"

Вывод:

$ bash ./initial_script3.sh
./initial_script3.sh: line 5: ${$path/\//\\/g}: bad substitution
Via bash: /home/django_auth_lifecycle/urls.py
Direct echo: \/ghome/django_auth_lifecycle/urls.py
Via bash (no dollar): \/ghome/django_auth_lifecycle/urls.py
./initial_script3.sh: line 14: \/ghome/django_auth_lifecycle/urls.py: No such file or directory
Via echo bash (no dollar): /home/django_auth_lifecycle/urls.py
Via sed (slash, quotes): \home\django_auth_lifecycle\urls.py
Via sed (slash): /home/django_auth_lifecycle/urls.py
Via sed (colon, quotes): \home\django_auth_lifecycle\urls.py
sed: -e expression #1, char 7: unterminated `s' command
Via sed (colon):
./initial_script3.sh: line 34: s:/:\\:g: No such file or directory
Via sed/<<< (colon): /home/django_auth_lifecycle/urls.py
./initial_script3.sh: line 38: s/\//\\:g: No such file or directory
Via sed/<<< (slash): /home/django_auth_lifecycle/urls.py
./initial_script3.sh: line 42: s/"\/"/"\\":g: No such file or directory
Via sed/<<< (slash, quotes): /home/django_auth_lifecycle/urls.py

Вывод с отладкой:

$ bash -x ./initial_script3.sh
+ origPath=/home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
./initial_script3.sh: line 5: ${$path/\//\\/g}: bad substitution
+ echo 'Via bash: /home/django_auth_lifecycle/urls.py'
Via bash: /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ echo 'Direct echo: \/ghome/django_auth_lifecycle/urls.py'
Direct echo: \/ghome/django_auth_lifecycle/urls.py
+ path='\/ghome/django_auth_lifecycle/urls.py'
+ echo 'Via bash (no dollar): \/ghome/django_auth_lifecycle/urls.py'
Via bash (no dollar): \/ghome/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path=echo
+ '\/ghome/django_auth_lifecycle/urls.py'
./initial_script3.sh: line 14: \/ghome/django_auth_lifecycle/urls.py: No such file or directory
+ echo 'Via echo bash (no dollar): /home/django_auth_lifecycle/urls.py'
Via echo bash (no dollar): /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
++ sed 's/\//\\/g'
++ echo /home/django_auth_lifecycle/urls.py
+ path='\home\django_auth_lifecycle\urls.py'
+ echo 'Via sed (slash, quotes): \home\django_auth_lifecycle\urls.py'
Via sed (slash, quotes): \home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ echo 'Via sed (slash): /home/django_auth_lifecycle/urls.py'
Via sed (slash): /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
++ sed 's:\/:\\:g'
++ echo /home/django_auth_lifecycle/urls.py
+ path='\home\django_auth_lifecycle\urls.py'
+ echo 'Via sed (colon, quotes): \home\django_auth_lifecycle\urls.py'
Via sed (colon, quotes): \home\django_auth_lifecycle\urls.py
+ path=/home/django_auth_lifecycle/urls.py
++ sed 's:/:\:g'
sed: -e expression #1, char 7: unterminated `s' command
++ echo /home/django_auth_lifecycle/urls.py
+ path=
+ echo 'Via sed (colon): '
Via sed (colon):
+ path=/home/django_auth_lifecycle/urls.py
+ path=sed
+ 's:/:\\:g'
./initial_script3.sh: line 34: s:/:\\:g: No such file or directory
+ echo 'Via sed/<<< (colon): /home/django_auth_lifecycle/urls.py'
Via sed/<<< (colon): /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path=sed
+ 's/\//\\:g'
./initial_script3.sh: line 38: s/\//\\:g: No such file or directory
+ echo 'Via sed/<<< (slash): /home/django_auth_lifecycle/urls.py'
Via sed/<<< (slash): /home/django_auth_lifecycle/urls.py
+ path=/home/django_auth_lifecycle/urls.py
+ path=sed
+ 's/"\/"/"\\":g'
./initial_script3.sh: line 42: s/"\/"/"\\":g: No such file or directory
+ echo 'Via sed/<<< (slash, quotes): /home/django_auth_lifecycle/urls.py'
Via sed/<<< (slash, quotes): /home/django_auth_lifecycle/urls.py