Linux command line: split a string

Question

I have long file with the following list:

/drivers/isdn/hardware/eicon/message.c//add_b1()
/drivers/media/video/saa7134/saa7134-dvb.c//dvb_init()
/sound/pci/ac97/ac97_codec.c//snd_ac97_mixer_build()
/drivers/s390/char/tape_34xx.c//tape_34xx_unit_check()
(PROBLEM)/drivers/video/sis/init301.c//SiS_GetCRT2Data301()
/drivers/scsi/sg.c//sg_ioctl()
/fs/ntfs/file.c//ntfs_prepare_pages_for_non_resident_write()
/drivers/net/tg3.c//tg3_reset_hw()
/arch/cris/arch-v32/drivers/cryptocop.c//cryptocop_setup_dma_list()
/drivers/media/video/pvrusb2/pvrusb2-v4l2.c//pvr2_v4l2_do_ioctl()
/drivers/video/aty/atyfb_base.c//aty_init()
/block/compat_ioctl.c//compat_blkdev_driver_ioctl()
....

It contains all the functions in the kernel code. The notation is file//function.

I want to copy some 100 files from the kernel directory to another directory, so I want to strip every line from the function name, leaving just the filename.

It's super-easy in python, any idea how to write a 1-liner in the bash prompt that does the trick?

Thanks,

Udi

Solution 1

cat "func_list" | sed "s#//.*##" > "file_list"

Didn't run it :)

Solution 2

You can use pure Bash:

while read -r line; do echo "${line%//*}"; done < funclist.txt

Edit:

The syntax of the echo command is doing the same thing as the sed command in Eugene's answer: deleting the "//" and everything that comes after.

Broken down:

"echo ${line}" is the same as "echo $line"
the "%" deletes the pattern that follows it if it matches the trailing portion of the parameter
"%" makes the shortest possible match, "%%" makes the longest possible
"//*" is the pattern to match, "*" is similar to sed's ".*"

See the Parameter Expansion section of the Bash man page for more information, including:

• using ${parameter#word} for matching the beginning of a parameter
• ${parameter/pattern/string} to do sed-style replacements
• ${parameter:offset:length} to retrieve substrings
• etc.

Solution 3

here's a one liner in (g)awk

awk -F"//" '{print $1}' file