bash：如何将脚本名称分配给变量并从另一个脚本调用它

Question

I have a simple bash script that works correctly on its own, and a second script, that at some point should call the first script and execute it. In the second script, I assign the first script's name into a variable and then try to call it with: sh ${VARIABLE}

The problem I face is:
while ${VARIABLE} correctly stores the name of the script, the line sh ${VARIABLE} returns an empty value, thus does not execute the script.

Relevant part of the code:

#!/bin/bash

comp(){
    # Check if user is root
    if [ ! $(whoami) == "root" ]; then
        echo "Need root!"
        exit 1
    fi
    export make="make -j4"
    cd ${THISCWD}/${THISPRG}/${SRCDIR}/
    PRGSCRIPT="${THISPRG}-1510.sh"
# echo $(pwd)
# echo $PRGSCRIPT
# echo $(ls | grep "20151013-b4-1510.sh")
# echo $(ls | grep "${PRGSCRIPT}")
    sh ${PRGSCRIPT}
}

The commented out echo, I included them in an attempt to troubleshot. When I uncomment them, the first three return the expected values, while the 4th returns empty line:

# echo $PRGSCRIPT
20151013-b4-1510.sh
# echo $(ls | grep "20151013-b4-1510.sh")
20151013-b4-1510.sh
# echo $(ls | grep "${PRGSCRIPT}")
   # (<- I get an empty line here)

When I run my script, I get a No such file or directory error.

I have been googling for answers and searched in Stackoverflow as well, but I think I am not using the correct search terms, because I get answers about how to pass variable values or arguments from one script to another.

I have been trying to resolve this for hours, with set -x; trap read debug set -x; trap read debug and putting echo everywhere to make sure all my variables and paths are correct.

I've trying adding quotes around my variable, removing quotes and curly brackets and explicitly assign the variable name: even then, the script called returns empty.

The script that I call starts with #!/bin/bash (absolutely no ^M or ^r or any Windows style newlines or symbols) and in my pc /bin/sh is a soft link to /bin/bash . Still, I tried calling the second script with /bin/bash instead of sh , which made no difference.

Also, since my script requires switch user, I made sure that all the variables are listed in the script when it's called.

If I pass all the variables and the function directly on the shell, and then call it comp , it executes correctly the second script.

I am pretty sure I am doing a typical newbie mistake here, and I would really appreciate any insight. Sorry for being so verbose, I didn't know how much detail to include.

---

Updated :

@shellter comments:

ls -l -- "$PRGSCRIPT" gives ls: cannot access 20151013-b4-1510.sh: No such file or directory , while echo $PRGSCRIPT returns the name of the file correctly.

I did not include all of the script, the first part sets all the variables, ( ${THISCWD} , ${THISPRG} etc). Also when I do the test echo $(pwd) it shows that I am in the correct path. I am getting more and more confused...

Also Windows editing was not involved in any part of the process, I used vi in Linux for both scripts and only in my local machine, no ftp involved. No spaces in the path either.

Regarding relevant mount output: I am not sure what you mean. The root partition is in /dev/sda1 and my home partition in /dev/sda5 . My $PATH correctly sees /bin , /usr/bin , etc

Thanks for your time - I am updating the question as you suggested, to avoid long comment list

More updates, in response to comments :

@ shellter

# mount | egrep 'sda1|sda5'
/dev/sda1 on / type ext4 (rw)
/dev/sda5 on /home type ext4 (rw)

I will make sure to double-check the permissions in the script folder (great script, btw :) - hope you don't mind that I will be using it!) however, since I actually su before running the script, I think it won't be a permissions problem

@couling

I did find a problem in this! I tested the outputs, as you suggested, in ht and got a non-printable character in every end of line:

│00000000 23 23 23 32 30 31 35 31-30 31 33 2d 62 34 2d 31 |###20151013-b4-1|                             │
│00000010 35 31 30 2e 73 68 23 23-23 0a                   |510.sh###?      |

All my lines end with an 0a character... Same in the ls.txt file. I have no idea how to fix this, any suggestions? Didn't think that vi and vim would add new line characters.

updated ls.txt

│00000000 74 6f 74 61 6c 20 36 34-0a 64 72 77 78 72 2d 78 |total 64?drwxr-x|                             ^
│00000010 72 2d 78 20 32 20 62 34-74 73 74 73 20 75 73 65 |r-x 2 b4tsts use|                             ▒
│00000020 72 73 20 34 30 39 36 20-4f 63 74 20 31 31 20 30 |rs 4096 Oct 11 0|                             ▒
│00000030 38 3a 30 32 20 32 30 31-35 31 30 30 31 0a 64 72 |8:02 20151001?dr|                             ▒
│00000040 77 78 72 2d 78 72 2d 78-20 32 20 62 34 74 73 74 |wxr-xr-x 2 b4tst|                             ▒
│00000050 73 20 75 73 65 72 73 20-34 30 39 36 20 4f 63 74 |s users 4096 Oct|                             ▒
│00000060 20 31 31 20 30 38 3a 30-32 20 32 30 31 35 31 30 | 11 08:02 201510|                             ▒
│00000070 30 32 0a 64 72 77 78 72-2d 78 72 2d 78 20 32 20 |02?drwxr-xr-x 2 |                             ▒
│00000080 62 34 74 73 74 73 20 75-73 65 72 73 20 34 30 39 |b4tsts users 409|                             ▒
│00000090 36 20 4f 63 74 20 31 31-20 30 38 3a 30 32 20 32 |6 Oct 11 08:02 2|                             ▒
│000000a0 30 31 35 31 30 30 33 0a-64 72 77 78 72 2d 78 72 |0151003?drwxr-xr|                             ▒
│000000b0 2d 78 20 32 20 62 34 74-73 74 73 20 75 73 65 72 |-x 2 b4tsts user|                             ▒
│000000c0 73 20 34 30 39 36 20 4f-63 74 20 31 31 20 30 38 |s 4096 Oct 11 08|                             ▒
│000000d0 3a 30 34 20 32 30 31 35-31 30 30 34 0a 64 72 77 |:04 20151004?drw|                             ▒
│000000e0 78 72 2d 78 72 2d 78 20-32 20 62 34 74 73 74 73 |xr-xr-x 2 b4tsts|                             ▒
│000000f0 20 75 73 65 72 73 20 34-30 39 36 20 4f 63 74 20 | users 4096 Oct |                             ▒
│00000100 31 31 20 30 37 3a 33 31-20 32 30 31 35 31 30 30 |11 07:31 2015100|                             ▒
│00000110 35 0a 64 72 77 78 72 2d-78 72 2d 78 20 32 20 62 |5?drwxr-xr-x 2 b|                             ▒
│00000120 34 74 73 74 73 20 75 73-65 72 73 20 34 30 39 36 |4tsts users 4096|                             ▒
│00000130 20 4f 63 74 20 31 36 20-32 32 3a 33 34 20 32 30 | Oct 16 22:34 20|                             ▒
│00000140 31 35 31 30 30 36 0a 64-72 77 78 72 2d 78 72 2d |151006?drwxr-xr-|                             ▒
│00000150 78 20 32 20 62 34 74 73-74 73 20 75 73 65 72 73 |x 2 b4tsts users|                             ▒
│00000160 20 34 30 39 36 20 4f 63-74 20 31 36 20 32 32 3a | 4096 Oct 16 22:|                             ▒
│00000170 33 34 20 32 30 31 35 31-30 30 37 0a 64 72 77 78 |34 20151007?drwx|                             ▒
│00000180 72 2d 78 72 2d 78 20 32-20 62 34 74 73 74 73 20 |r-xr-x 2 b4tsts |                             ▒
│00000190 75 73 65 72 73 20 34 30-39 36 20 4f 63 74 20 31 |users 4096 Oct 1|                             ▒
│000001a0 36 20 32 32 3a 33 34 20-32 30 31 35 31 30 30 38 |6 22:34 20151008|  

Part of the output: I also have the 0a characters here. I checked all the characters shown as ? and they all are 0a

updated

In the end, I copied most parts of the script minus comments and echo in a new file and now, for some reason, it works as expected...

I still have no idea what happened or what was my problem.

I thank you all very much for your assistance, I've learned a few things in the process. I much appreciate you all taking the time to help me out.

Answer 1

It is very hard to give a definitive answer on this but it looks like there is a non-printable character getting in there somewhere. By non-printable I'm referring to \\r and other characters. I know you've stated that there is no \\r in the variable.

This could be either in the variable or the file name.

I'd do an ls -l > ls.txt and run your script to echo "###${PRGSCRIPT}###" > prgscript.txt . I'd then find a decent hex editor to analyse the result (one which shows the askii along side the hex). From what you've posted here I'd expect to see a discrepancy somewhere in the output (quite possibly involving a non-printable character).

Pay extra attention to new line characters before the trailing ### in the variable echo.

Answer 2

Without your full environment I have to follow couling's comment about how hard it is to give a definitive answer. But I spot a embedded in your script so some tips from years of scripting follow:

• Always resolve $0 to absolute path names, especially if your script uses commands.

   pwd0="$PWD"; \nname0="$0"; \nif [[ "$name0" != /* ]];  then name0="$pwd0/$name0";  fi; \n$name0-1510;  #assure execute matching "1510" program IN SAME DIRECTORY  

  This is very important if you want to execute other scripts in the same directory, which does not appear in PATH (ignoring ".", which commands invalidate). This copes with assorted strange games that can be played with PATH and absolute paths to scripts across behaviors of different operating systems and shells.
• On key variables you are having trouble with use the :? notation to fail with error if a variable is not well defined:

   PRGSCRIPT="${THISPRG:?"$LINENO: THISPRG not defined"}-1510.sh"  

  Admittedly this is not your current problem, but a good idea at key points.

Answer 3

First, check the status code after the cd , to see whether it worked.

Second, you write that you verified that PRGSCRIPT has the value 20151013-b4-1510.sh . Now we have three possibilities:

1. Either the shell finds a readable file of this name, in which case it will execute it somehow (and if you want to know what's going on inside this file, you can switch on a trace using the -x switch), or

2. The shell will output an error message

In theory, we also have the case that the file contains no executable commands (only comment lines), but this is something you can investigate separately.

For example, doing a

cat $PRGSCRIPT
sh -x $PRGSCRIPT

should reveal what's going on (unless you have redirected stdout and stderr of the calling script to the bit bucket).