Debug shell script

[email protected]:~$ cat b.sh
#!/bin/bashdir=`pwd`dir=$dir‘/‘for f in `ls *.png`do  echo $dir$fdone

Check the execution of each line of code:

[email protected]:~$ bash -x b.sh++ pwd+ dir=/home/wade+ dir=/home/wade/++ ls chrome_1407299385726.png chrome_1427299385726.png+ for f in ‘`ls *.png`‘+ echo /home/wade/chrome_1407299385726.png/home/wade/chrome_1407299385726.png+ for f in ‘`ls *.png`‘+ echo /home/wade/chrome_1427299385726.png

Further, we can see that the Code executed corresponds to the row number:

[email protected]:~$ export PS4=‘+${BASH_SOURCE}:${LINENO}:${FUNCNAME[0]}: ‘[email protected]:~$ bash -x b.sh++b.sh:2:: pwd+b.sh:2:: dir=/home/wade+b.sh:3:: dir=/home/wade/++b.sh:8:: ls chrome_1407299385726.png chrome_1427299385726.png+b.sh:4:: for f in ‘`ls *.png`‘+b.sh:7:: echo /home/wade/chrome_1407299385726.png/home/wade/chrome_1407299385726.png+b.sh:4:: for f in ‘`ls *.png`‘+b.sh:7:: echo /home/wade/chrome_1427299385726.png

Specify the part of the script to run the detailed line number, and ignore the rest:

[email protected]:~$ cat b.sh #!/bin/bashdir=`pwd`dir=$dir‘/‘#this line above won‘t log out set -xfor f in `ls *.png`do  echo $dir$fdoneset +x#the follow line won‘t log out echo ‘end‘abc=‘new var‘

Running output:

[email protected]:~$ ./b.sh++./b.sh:10:: ls chrome_1407299385726.png chrome_1427299385726.png+./b.sh:6:: for f in ‘`ls *.png`‘+./b.sh:9:: echo /home/wade/chrome_1407299385726.png/home/wade/chrome_1407299385726.png+./b.sh:6:: for f in ‘`ls *.png`‘+./b.sh:9:: echo /home/wade/chrome_1427299385726.png/home/wade/chrome_1427299385726.png+./b.sh:11:: set +xend