Understanding $() (and for-loops) in bash
I have a directory with git inside and git branch gives me the following output:
$ git branch
branch1
* branch2
master
The * marks the current branch. I would like to use this output in a script. So I loop over the lines like this:
$ for line in $(git branch); do echo "${line}"; done;
branch1
README.txt
branch2
master
Questions:
What happened to the * and why do I see README.txt[1]?
How can I loop over the lines returned by a normal git branch exactly as they are, with * and a space?
P.S.: I am on a Mac right now.
[1] (or any other file in the repository but this one only has one file "README.txt")
bash command-substitution for loop-device
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
asked Mar 6 at 15:30
scrrrscrrr
288238
add a comment |
I have a directory with git inside and git branch gives me the following output:
$ git branch
branch1
* branch2
master
The * marks the current branch. I would like to use this output in a script. So I loop over the lines like this:
$ for line in $(git branch); do echo "${line}"; done;
branch1
README.txt
branch2
master
Questions:
What happened to the * and why do I see README.txt[1]?
How can I loop over the lines returned by a normal git branch exactly as they are, with * and a space?
P.S.: I am on a Mac right now.
[1] (or any other file in the repository but this one only has one file "README.txt")
bash command-substitution for loop-device
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
asked Mar 6 at 15:30
scrrrscrrr
288238
See mywiki.wooledge.org/BashFAQ/001, particularly Why you don't read lines with "for"
– glenn jackman
Mar 6 at 17:18
add a comment |
I have a directory with git inside and git branch gives me the following output:
$ git branch
branch1
* branch2
master
The * marks the current branch. I would like to use this output in a script. So I loop over the lines like this:
$ for line in $(git branch); do echo "${line}"; done;
branch1
README.txt
branch2
master
Questions:
What happened to the * and why do I see README.txt[1]?
How can I loop over the lines returned by a normal git branch exactly as they are, with * and a space?
P.S.: I am on a Mac right now.
[1] (or any other file in the repository but this one only has one file "README.txt")
bash command-substitution for loop-device
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
asked Mar 6 at 15:30
scrrrscrrr
288238
I have a directory with git inside and git branch gives me the following output:
$ git branch
branch1
* branch2
master
The * marks the current branch. I would like to use this output in a script. So I loop over the lines like this:
$ for line in $(git branch); do echo "${line}"; done;
branch1
README.txt
branch2
master
Questions:
What happened to the * and why do I see README.txt[1]?
How can I loop over the lines returned by a normal git branch exactly as they are, with * and a space?
P.S.: I am on a Mac right now.
[1] (or any other file in the repository but this one only has one file "README.txt")
bash command-substitution for loop-device
bash command-substitution for loop-device
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
asked Mar 6 at 15:30
scrrrscrrr
288238
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
asked Mar 6 at 15:30
scrrrscrrr
288238
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
edited Mar 6 at 15:50
Rui F Ribeiro
41.8k1483142
41.8k1483142
asked Mar 6 at 15:30
scrrrscrrr
288238
asked Mar 6 at 15:30
scrrrscrrr
288238
asked Mar 6 at 15:30
scrrrscrrr
288238
288238
See mywiki.wooledge.org/BashFAQ/001, particularly Why you don't read lines with "for"
– glenn jackman
Mar 6 at 17:18
add a comment |
See mywiki.wooledge.org/BashFAQ/001, particularly Why you don't read lines with "for"
– glenn jackman
Mar 6 at 17:18
See mywiki.wooledge.org/BashFAQ/001, particularly Why you don't read lines with "for"
– glenn jackman
Mar 6 at 17:18
See mywiki.wooledge.org/BashFAQ/001, particularly Why you don't read lines with "for"
– glenn jackman
Mar 6 at 17:18
add a comment |
1 Answer
1
active
oldest
votes
When $(git branch) is expanded for the for loop to loop over it, it expands to the multi-line string
branch1
* branch2
master
Since the command substitution is unquoted, this is then split on spaces, tabs and newlines (by default) into the four words
branch1 * branch2 master
Each word then undergoes filename generation (globbing). The second word, *, will be replaced by all filenames in your current directory. This appears to be one file only, README.txt.
The final list that the loop will loop over is therefore
branch1 README.txt branch2 master
Instead, if you just want to output this in a script, use
git branch
without doing anything more.
If you want to save the output in a variable, use
branches=$( git branch )
Would you want to get the name of the current branch, then extract the branch whose name is preceded by a *:
curr_branch=$( git branch | awk '/^*/ { print $2 }' )
Would you want to iterate over the output of git branch, use a while loop:
git branch |
while read -r star name; do
if [ -z "$name" ]; then
name=$star
printf 'One branch is "%s"n' "$name"
else
printf 'The current branch is "%s"n' "$name"
fi
done
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
git rev-parse --abbrev-ref HEADto show only current branch.
– pfnuesel
Mar 6 at 15:46
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
add a comment |
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1 Answer
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active
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1 Answer
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active
oldest
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oldest
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oldest
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When $(git branch) is expanded for the for loop to loop over it, it expands to the multi-line string
branch1
* branch2
master
Since the command substitution is unquoted, this is then split on spaces, tabs and newlines (by default) into the four words
branch1 * branch2 master
Each word then undergoes filename generation (globbing). The second word, *, will be replaced by all filenames in your current directory. This appears to be one file only, README.txt.
The final list that the loop will loop over is therefore
branch1 README.txt branch2 master
Instead, if you just want to output this in a script, use
git branch
without doing anything more.
If you want to save the output in a variable, use
branches=$( git branch )
Would you want to get the name of the current branch, then extract the branch whose name is preceded by a *:
curr_branch=$( git branch | awk '/^*/ { print $2 }' )
Would you want to iterate over the output of git branch, use a while loop:
git branch |
while read -r star name; do
if [ -z "$name" ]; then
name=$star
printf 'One branch is "%s"n' "$name"
else
printf 'The current branch is "%s"n' "$name"
fi
done
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
git rev-parse --abbrev-ref HEADto show only current branch.
– pfnuesel
Mar 6 at 15:46
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
add a comment |
When $(git branch) is expanded for the for loop to loop over it, it expands to the multi-line string
branch1
* branch2
master
Since the command substitution is unquoted, this is then split on spaces, tabs and newlines (by default) into the four words
branch1 * branch2 master
Each word then undergoes filename generation (globbing). The second word, *, will be replaced by all filenames in your current directory. This appears to be one file only, README.txt.
The final list that the loop will loop over is therefore
branch1 README.txt branch2 master
Instead, if you just want to output this in a script, use
git branch
without doing anything more.
If you want to save the output in a variable, use
branches=$( git branch )
Would you want to get the name of the current branch, then extract the branch whose name is preceded by a *:
curr_branch=$( git branch | awk '/^*/ { print $2 }' )
Would you want to iterate over the output of git branch, use a while loop:
git branch |
while read -r star name; do
if [ -z "$name" ]; then
name=$star
printf 'One branch is "%s"n' "$name"
else
printf 'The current branch is "%s"n' "$name"
fi
done
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
git rev-parse --abbrev-ref HEADto show only current branch.
– pfnuesel
Mar 6 at 15:46
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
add a comment |
When $(git branch) is expanded for the for loop to loop over it, it expands to the multi-line string
branch1
* branch2
master
Since the command substitution is unquoted, this is then split on spaces, tabs and newlines (by default) into the four words
branch1 * branch2 master
Each word then undergoes filename generation (globbing). The second word, *, will be replaced by all filenames in your current directory. This appears to be one file only, README.txt.
The final list that the loop will loop over is therefore
branch1 README.txt branch2 master
Instead, if you just want to output this in a script, use
git branch
without doing anything more.
If you want to save the output in a variable, use
branches=$( git branch )
Would you want to get the name of the current branch, then extract the branch whose name is preceded by a *:
curr_branch=$( git branch | awk '/^*/ { print $2 }' )
Would you want to iterate over the output of git branch, use a while loop:
git branch |
while read -r star name; do
if [ -z "$name" ]; then
name=$star
printf 'One branch is "%s"n' "$name"
else
printf 'The current branch is "%s"n' "$name"
fi
done
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
When $(git branch) is expanded for the for loop to loop over it, it expands to the multi-line string
branch1
* branch2
master
Since the command substitution is unquoted, this is then split on spaces, tabs and newlines (by default) into the four words
branch1 * branch2 master
Each word then undergoes filename generation (globbing). The second word, *, will be replaced by all filenames in your current directory. This appears to be one file only, README.txt.
The final list that the loop will loop over is therefore
branch1 README.txt branch2 master
Instead, if you just want to output this in a script, use
git branch
without doing anything more.
If you want to save the output in a variable, use
branches=$( git branch )
Would you want to get the name of the current branch, then extract the branch whose name is preceded by a *:
curr_branch=$( git branch | awk '/^*/ { print $2 }' )
Would you want to iterate over the output of git branch, use a while loop:
git branch |
while read -r star name; do
if [ -z "$name" ]; then
name=$star
printf 'One branch is "%s"n' "$name"
else
printf 'The current branch is "%s"n' "$name"
fi
done
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
edited Mar 6 at 15:46
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
answered Mar 6 at 15:40
Kusalananda♦Kusalananda
138k17258428
138k17258428
git rev-parse --abbrev-ref HEADto show only current branch.
– pfnuesel
Mar 6 at 15:46
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
add a comment |
git rev-parse --abbrev-ref HEADto show only current branch.
– pfnuesel
Mar 6 at 15:46
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
git rev-parse --abbrev-ref HEAD to show only current branch.– pfnuesel
Mar 6 at 15:46
git rev-parse --abbrev-ref HEAD to show only current branch.– pfnuesel
Mar 6 at 15:46
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
1. Reason I do this I want to also do a $(git config branch.$line.description) and append it to the branch name, but I also want to keep the asterisk. 2. Thank you for this excellent write up!
– scrrr
Mar 6 at 16:07
add a comment |
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See mywiki.wooledge.org/BashFAQ/001, particularly Why you don't read lines with "for"
– glenn jackman
Mar 6 at 17:18