How to write value1 || value2 in shell? - shell

I would make a simple script in shell and put a default value in case the user enters nothing. Here is my script:
git add -A
git commit -m "checkpoint commit"
git push
I would make something like
git add -A
git commit -m ($1 || "checkpoint commit")
git push

You can use
git commit -m "${1:-checkpoint commit}"
If $1 is set, ${1:-checkpoint commit} will expand to the value of $1.
If $1 is not set, it will expand to whatever is after the :- (ie "checkpoint commit" in this example).

Related

Git alias for commit with branch name

I'm trying to create a simple bash alias to commit with my branch name in MacOs. For instance, if my branch if CS-12 I'd usually commit as follows:
git commit /file/location/myfile -m "CS-12 my message goes in here"
So I'm trying to create an alias which will receive only the file name and the message, ie:
gcm /file/location/myfile "my message goes in here"
I've got the following but it's not working:
alias gcm="echo git commit $1 -m \"$(current_branch) - $2\""
where current_branch is the function:
function current_branch() {
ref=$(git symbolic-ref HEAD 2> /dev/null) || \
ref=$(git rev-parse --short HEAD 2> /dev/null) || return
echo ${ref#refs/heads/}
}
which does work.
The output of running my alias:
gcm src/pages/register/Register.js "aasdasd asdasd"
is giving me back:
git commit -m master - src/pages/register/Register.js aasdasd asdasd
any idea what I'm doing wrong? Bash is not my area of expertise.
Thanks
The escaped quotes are 'stripped' by alias, so you need to escape them once more:
alias x="echo \\\"foo\\\""
x
"foo"
aliases do not take parameters. Just write a function:
gcm() { git commit "$1" -m "$(current_branch) - $2"; }
Note that there's really no need for aliases, and you shouldn't use them. Since at least 1996, the bash man page has stated: "For almost every purpose, aliases are superseded by shell functions."

PowerShell - git checkout -B without reset or alternatives?

Related to this question: git checkout -B without reset or alternatives?
I want to change branches, but create the branch if it doesn't exist. -B doesn't work, as I have un-pushed commits on the branches and don't want them to be reset.
How would you write this: git checkout branchname -- 2>/dev/null || git checkout -b branchname in powershell?
The equivalent of this shell command...
git checkout branchname -- 2>/dev/null || git checkout -b branchname
...in PowerShell would be this:
$branchname = "your-branch"
git checkout $branchname 2>&1 | Out-Null
if (-not $?) {
git checkout -b $branchname
}
It uses the $? automatic variable, to determine if the last command succeeded. Also, error stream redirection and Out-Null.
Note that in PowerShell 7 (Core), || and && are also available, called pipeline chain operators.
git checkout $branchname || git checkout -b $branchname

How does eval stop the pathspec errors in this script?

I want to automate the many version control steps of Git. I was successful until I used git commit -S -m ${var} in my Bash script. This line gives me (pathspec errors x # of word) - 1... unless I use eval. How does eval make my script work?
I thought this article had the answer, but my issue involves a string, not an array.
Gif video of the broken vs. working Bash script
Broken code
brokenCommitCode () {
# Give it a multi-word, space-separated message
read -p 'Commit message (use quotes): ' commitMsg
commitMsg="'${commitMsg}'"
echo ${commitMsg}
git add -A &&
git commit -S -m ${commitMsg}
}
Working code
workingCommitCode () {
read -p 'Commit message (use quotes): ' commitMsg
commitMsg="'${commitMsg}'"
echo ${commitMsg}
git add -A &&
eval git commit -S -m ${commitMsg}
}
I expected the brokenCommitCode to commit properly with the message I enter on the prompt. The actual result is a pathspec error when it reaches git commit -S -m ${commitMsg}. How does eval make this work?
I'm using GNU bash, version 4.4.19(1)-release (x86_64-pc-msys) with git version 2.16.2.windows.1 on a Windows 8.1 PC.
Correct fix is
funname() {
read -p 'Commit message (use quotes): ' commitMsg
echo "${commitMsg}"
git add -A &&
git commit -S -m "${commitMsg}"
}
Why eval seems to fix:
single quotes where added to commitMsg variable (seems intent was to prevent message argument to be split on a whitespace)
looking what happens with the following message:
commitMsg="this is a message"
git commit -S -m ${commitMsg}
git commit -S -m this is a message
[error because "is" "a" "message" are taken as different additional arguments]
however it doesn't prevent because single quote is not re-interpreted but is like any other character in variable content
following with the example
git commit -S -m ${commitMsg}
git commit -S -m \'this is a message\'
[error "is" "a" "message'" are taken as different additional arguments]
with eval the single quotes are re-interpreted but also any other character which has a particular meaning in bash (;, &, ${..}, ..)
Suppose for example the following commit message which can inject arbitrary command.
commitMsg="message'; ls -l; echo 'done"
git commit -S -m 'message'; ls -l; echo 'done'

change directory in bash is not affecting the post-commit hook

i've made the following bash script to commit the parent repo after some change in submodule.
it's all about that the script want to cd .. to check the parent repo current branch but the problem is that the cd .. is not affecting the upcoming commands because i guess the subshell
i've tried to run
1- cd ../ && before each command
2- make alias but didn't succeed
3- run exec but the script didn't continued
#!/bin/sh
#
# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments. The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# To enable this hook, rename this file to "post-commit".
commit_msg= git log -1 --pretty=%B
if [[ $(git branch | grep \* | cut -d ' ' -f2) == "int1177/next" ]]; then
cd ..
if [[ $(git branch | grep \* | cut -d ' ' -f2) == "B0/next" ]]; then
git add 6_Tests
git commit -m "bs esss"
echo "development branch B0/next has now new commit"
else
echo "development branch isn't B0/next"
fi
else
echo "current branch isn't int1177/next"
fi
Actually, this particular problem is not a bash issue, but rather a Git issue.
Why doesn't "cd" work in a shell script? is valid in general, and is a suitable answer to many other questions. But this particular post-commit hook is trying to chdir out of a submodule into its parent superproject, then make a commit within the parent superproject. That is possible. It may be a bad idea for other reasons—in general it's unwise to have Git commit hooks create commits, even in other repositories1—but in this particular case you're running into the fact that Git finds its directories through environment variables.
In particular, there's an environment variable GIT_DIR that tells Git: The .git directory containing the repository is at this path. When Git runs a Git hook, Git typically sets $GIT_DIR to . or .git. If $GIT_DIR is not set, Git will find the .git directory by means of a directory-tree search, but if $GIT_DIR is set, Git assumes that $GIT_DIR is set correctly.
The solution is to unset GIT_DIR:
unset GIT_DIR
cd ..
The rest of the sub-shell commands will run in the one-step-up directory, and now that $GIT_DIR is no longer set, Git will search the superproject's work-tree for the .git directory for the superproject.
As an aside, this:
$(git branch | grep \* | cut -d ' ' -f2)
is a clumsy way to get the name of the current branch. Use:
git rev-parse --abbrev-ref HEAD
instead, here. (The other option is git symbolic-ref --short HEAD but that fails noisily with a detached HEAD, while you probably want the quiet result to be just the word HEAD, which the rev-parse method will produce.)
1The main danger in this case is that the superproject repository is not necessarily in any shape to handle a commit right now. Edit: or, as discovered in this comment, is not even set up to be a superproject for that submodule, yet, much less to have a submodule-updating commit added.

ZSH alias with parameter

I am trying to make an alias with parameter for my simple git add/commit/push.
I've seen that a function could be used as an alias, so I tried but I didn't make it.
Before I had:
alias gitall="git add . ; git commit -m 'update' ; git push"
But I want to be able to modify my commits:
function gitall() {
"git add ."
if [$1 != ""]
"git commit -m $1"
else
"git commit -m 'update'"
fi
"git push"
}
If you really need to use an alias with a parameter for some reason, you can hack it by embedding a function in your alias and immediately executing it:
alias example='f() { echo Your arg was $1. };f'
I see this approach used a lot in .gitconfig aliases.
You can't make an alias with arguments*, it has to be a function. Your function is close, you just need to quote certain arguments instead of the entire commands, and add spaces inside the [].
gitall() {
git add .
if [ "$1" != "" ] # or better, if [ -n "$1" ]
then
git commit -m "$1"
else
git commit -m update
fi
git push
}
*: Most shells don't allow arguments in aliases, I believe csh and derivatives do, but you shouldn't be using them anyway.
I used this function in .zshrc file:
function gitall() {
git add .
if [ "$1" != "" ]
then
git commit -m "$1"
else
git commit -m update # default commit message is `update`
fi # closing statement of if-else block
git push origin HEAD
}
Here git push origin HEAD is responsible to push your current branch on remote.
From command prompt run this command: gitall "commit message goes here"
If we just run gitall without any commit message then the commit message will be update as the function said.
"git add ." and the other commands between " are just strings for bash, remove the "s.
You might want to use [ -n "$1" ] instead in your if body.
I tried the accepted answer (Kevin's) but was getting the following error
defining function based on alias `gitall'
parse error near `()'
Hence changed the syntax to this, based on the git issue and it worked.
function gitall {
git add .
if [ "$1" != "" ]
then
git commit -m "$1"
else
git commit -m update
fi
git push
}
I can easily add params just using $1.
Eg:
alias gsf="git show --name-only $1"
works just fine. To call it I just use gsf 2342aa225

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