How to iterate through all git branches using bash script

How can I iterate through all the local branches in my repository using bash script. I need to iterate and check is there any difference between the branch and some remote branches. Ex

for branch in $(git branch); 
do
    git log --oneline $branch ^remotes/origin/master;
done

I need to do something like given above, but the issue I'm facing is $(git branch) gives me the folders inside the repository folder along with the branches present in the repository.

Is this the correct way to solve this issue? Or is there another way to do it?

Thank you

You should not use git branch when writing scripts. Git provides a “plumbing” interface that is explicitly designed for use in scripting (many current and historical implementations of normal Git commands (add, checkout, merge, etc.) use this same interface).

The plumbing command you want is git for-each-ref:

git for-each-ref --shell \
  --format='git log --oneline %(refname) ^origin/master' \
  refs/heads/

^{Note: You do not need the remotes/ prefix on the remote ref unless you have other refs that cause origin/master to match multiple places in the ref name search path (see “A symbolic ref name. …” in the Specifying Revisions section of git-rev-parse(1)). If you are trying to explictly avoid ambiguity, then go with the full ref name: refs/remotes/origin/master.}

You will get output like this:

git log --oneline 'refs/heads/master' ^origin/master
git log --oneline 'refs/heads/other' ^origin/master
git log --oneline 'refs/heads/pu' ^origin/master

You can pipe this output into sh.

If you do not like the idea of generating the shell code, you could give up a bit of robustness^* and do this:

for branch in $(git for-each-ref --format='%(refname)' refs/heads/); do
    git log --oneline "$branch" ^origin/master
done

^{* Ref names should be safe from the shell’s word splitting (see git-check-ref-format(1)). Personally I would stick with the former version (generated shell code); I am more confident that nothing inappropriate can happen with it.}

Since you specified bash and it supports arrays, you could maintain safety and still avoid generating the guts of your loop:

branches=()
eval "$(git for-each-ref --shell --format='branches+=(%(refname))' refs/heads/)"
for branch in "${branches[@]}"; do
    # …
done

You could do something similar with $@ if you are not using a shell that supports arrays (set -- to initialize and set -- "$@" %(refname) to add elements).

This is because git branch marks the current branch with an asterisk, e.g.:

$ git branch
* master
  mybranch
$ 

so $(git branch) expands to e.g. * master mybranch, and then the * expands to the list of files in the current directory.

I don't see an obvious option for not printing the asterisk in the first place; but you could chop it off:

$(git branch | cut -c 3-)

The bash builtin, mapfile, is built for this

all git branches: git branch --all --format='%(refname:short)'

all local git branches: git branch --format='%(refname:short)'

all remote git branches: git branch --remotes --format='%(refname:short)'

iterate through all git branches: mapfile -t -C my_callback -c 1 < <( get_branches )

example:

my_callback () {
  INDEX=${1}
  BRANCH=${2}
  echo "${INDEX} ${BRANCH}"
}
get_branches () {
  git branch --all --format='%(refname:short)'
}
# mapfile -t -C my_callback -c 1 BRANCHES < <( get_branches ) # if you want the branches that were sent to mapfile in a new array as well
# echo "${BRANCHES[@]}"
mapfile -t -C my_callback -c 1 < <( get_branches )

for the OP's specific situation:

#!/usr/bin/env bash


_map () {
  ARRAY=${1?}
  CALLBACK=${2?}
  mapfile -t -C "${CALLBACK}" -c 1 <<< "${ARRAY[@]}"
}


get_history_differences () {
  REF1=${1?}
  REF2=${2?}
  shift
  shift
  git log --oneline "${REF1}" ^"${REF2}" "${@}"
}


has_different_history () {
  REF1=${1?}
  REF2=${2?}
  HIST_DIFF=$( get_history_differences "${REF1}" "${REF2}" )
  return $( test -n "${HIST_DIFF}" )
}


print_different_branches () {
  read -r -a ARGS <<< "${@}"
  LOCAL=${ARGS[-1]?}
  for REMOTE in "${SOME_REMOTE_BRANCHES[@]}"; do
    if has_different_history "${LOCAL}" "${REMOTE}"; then
      # { echo; echo; get_history_differences "${LOCAL}" "${REMOTE}" --color=always; } # show differences
      echo local branch "${LOCAL}" is different than remote branch "${REMOTE}";
    fi
  done
}


get_local_branches () {
  git branch --format='%(refname:short)'
}


get_different_branches () {
  _map "$( get_local_branches )" print_different_branches
}


# read -r -a SOME_REMOTE_BRANCHES <<< "${@}" # use this instead for command line input
declare -a SOME_REMOTE_BRANCHES
SOME_REMOTE_BRANCHES=( origin/master remotes/origin/another-branch another-remote/another-interesting-branch )
DIFFERENT_BRANCHES=$( get_different_branches )

echo "${DIFFERENT_BRANCHES}"

source: https://stackoverflow.com/questions/51696931/list-all-local-git-branches-without-an-asterisk?noredirect=1&lq=1#comment90359143_51697007

I iterate as it for example :

for BRANCH in `git branch --list|sed 's/\*//g'`;
  do 
    git checkout $BRANCH
    git fetch
    git branch --set-upstream-to=origin/$BRANCH $BRANCH
  done
git checkout master;

Easiest option to remember in my opinion:

git branch | grep "[^* ]+" -Eo

Output:

bamboo
develop
master

Grep's -o option (--only-matching) restricts the output to only the matching parts of the input.

Since neither space nor * are valid in Git branch names, this returns the list of branches without the extra characters.

Edit: If you're in 'detached head' state, you'll need to filter out the current entry:

git branch --list | grep -v "HEAD detached" | grep "[^* ]+" -oE

I would suggest $(git branch|grep -o "[0-9A-Za-z]\+") if your local branches are named by digits, a-z, and/or A-Z letters only

The accepted answer is correct and really should be the approach used, but solving the problem in bash is a great exercise in understanding how shells work. The trick to doing this using bash without performing additional text manipulation, is to ensure the output of git branch never gets expanded as part of a command to be executed by the shell. This prevents the asterisk from ever being expanding in the file name expansion (step 8) of shell expansion (see http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_04.html)

Use the bash while construct with a read command to chop the git branch output into lines. The '*' will be read in as a literal character. Use a case statement to match it, paying special attention to the matching patterns.

git branch | while read line ; do                                                                                                        
    case $line in
        \*\ *) branch=${line#\*\ } ;;  # match the current branch
        *) branch=$line ;;             # match all the other branches
    esac
    git log --oneline $branch ^remotes/origin/master
done

The asterisks in both the bash case construct and in the parameter substitution need to be escaped with backslashes to prevent the shell interpreting them as pattern matching characters. The spaces are also escaped (to prevent tokenization) because you are literally matching '* '.

Keep it simple

The simple way of getting branch name in loop using bash script.

#!/bin/bash

for branch in $(git for-each-ref --format='%(refname)' refs/heads/); do
    echo "${branch/'refs/heads/'/''}" 
done

Output:

master
other

What I ended up doing, applied to your question (& inspired by ccpizza mentioning tr):

git branch | tr -d ' *' | while IFS='' read -r line; do git log --oneline "$line" ^remotes/origin/master; done

(I use while loops a lot. While for particular things you'd definitely want to use a pointed variable name ["branch", for example], most of the time I am only concerned with doing something with each line of input. Using 'line' here instead of 'branch' is a nod to reusability/muscle memory/efficiency.)

Googlian's answer, but without using for

git for-each-ref --format='%(refname:lstrip=-1)' refs/heads/

for branch in "$(git for-each-ref --format='%(refname:short)' refs/heads)"; do
	...
done

This uses git plumbing commands, which are designed for scripting. It's also simple and standard.

Reference: Git's Bash completion

If you're at this state:

git branch -a

* master

  remotes/origin/HEAD -> origin/master

  remotes/origin/branch1

  remotes/origin/branch2

  remotes/origin/branch3

  remotes/origin/master

And you run this code:

git branch -a | grep remotes/origin/*

for BRANCH in `git branch -a | grep remotes/origin/*` ;

do
    A="$(cut -d'/' -f3 <<<"$BRANCH")"
	echo $A
  
done        

You'll get this result:

branch1

branch2

branch3

master

Extending on from @finn's answer (thank you!), the following will let you iterate over the branches without creating an intervening shell script. It's robust enough, as long as there's no newlines in the branch name :)

git for-each-ref --format='%(refname)' refs/heads  | while read x ; do echo === $x === ; done

The while loop runs in a subshell, which is usually fine unless you're setting shell variables that you want to access in the current shell. In that case you use process substitution to reverse the pipe:

while read x ; do echo === $x === ; done < <( git for-each-ref --format='%(refname)' refs/heads )

List heads (branches) in the local repository

git show-ref --heads

• git show-ref - List references in a local repository
  • --heads only list heads (and not tags)

This will list the heads something like

682e47c01dc8d0f4e4102f183190a48aaf34a3f0 refs/heads/main
....

so if you're only interested in the name, you can use something like sed to obtain the output you want

git show-ref --heads | sed 's/.*refs\/heads\///'

Iterate through the branches

With this output you can easily iterate through it, say using a bash loop, xargs, whatever floats your boat

for SHA in $(git show-ref --heads | awk '{ print $1 }'); do
 echo "magic! $SHA"
done

• git show-ref --heads get the branches as per above
• awk '{ print $1 }' obtain the SHA
• echo "magic! $SHA" <- this is where you would do your magic

#/bin/bash
for branch in $(git branch -r); 
do
    echo $branch
done

Of course in theory one should use a special interface that Git indeed has for use when scripting. But often you want something simpler — handy for a oneliner. Something that doesn't urge you remember stuff like git for-each-ref --format … refs … amen. And it's UNIX anyways finally. Then it goes like that:

1. There's an utility widely known for its obscure but a terse way to print the last column.
2. git branch puts asterisk before the branch name. Meaning we're seemingly always interested in the last column exactly.

Resulting:

git branch | awk '{print $NF}'